Patent Publication Number: US-9430261-B2

Title: Controlling apparatus, and controlling method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2013-250600 filed on Dec. 3, 2013, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiments discussed herein are related to a controlling program, a controlling apparatus, and a controlling method. 
     BACKGROUND 
     In the related art, in a system including a virtual machine generated on a physical device, there is provided a technology of executing a duplication (back-up) process of a storage area used by the virtual machine. For example, a back-up device which is a physical device is provided in such a system, and there is provided a technology of executing the duplication process by the back-up device. 
     Japanese Laid-open Patent Publication No. 2008-123205 is an example of the related art. 
     Herein, in order to reduce delay of the duplication process due to an increase in load of the process of the back-up device, the following process is executed in the system described above. For example, in the back-up device, a duplication process virtual machine which is a virtual machine for executing the duplication process is operated for each duplication process, and when the duplication process is delayed, the duplication process virtual device which is a factor of the delay is moved to a physical device other than the back-up device. 
     As an index for specifying the factor of the delay of the duplication process, a load of a route which connects devices to each other is provided, in addition to loads of a central processing unit (CPU) and a memory of the duplication process virtual machine operated on the back-up device. For example, the duplication process virtual machine including a CPU and a memory having loads equal to or greater than a threshold value is considered as a factor of the delay of the duplication process. 
     Herein, a route for connecting the back-up device and a memory device at a duplication destination of the duplication process may be redundant. In this case, any of the plurality of redundant routes may be used in the plurality of duplication process virtual machines operated in the back-up device. Accordingly, when the route is redundant, although the route having a load equal to or greater than a threshold value may be specified as a factor of the delay of the duplication process, it is difficult to specify the duplication process virtual machine using the specified route. Therefore, when the route is redundant, it is difficult to specify the duplication process virtual machine moved to the physical device other than the back-up device, by only specifying the route which is the factor of the delay. Thus, when the route is redundant, in a case where the route is the factor of the delay of the duplication process, it may be difficult to complete the duplication process within a regulated time. 
     According to an embodiment, an object of the disclosure is to suppress the delay of the duplication process, when the route is the factor of the delay of the duplication process. 
     SUMMARY 
     According to an aspect of the invention, a controlling method realized by a computer connected to a plurality of physical devices in which respective virtual machines (VMs) are operated and a process device which is connected to the plurality of physical devices with a plurality of routes and in which a plurality of duplication process VMs for executing a duplication process of duplicating data used by the plurality of VMs to a memory device, the method includes: acquiring loads of the plurality of routes and percentages of completion of the duplication process executed by the plurality of duplication process VMs; and, when incompletion of the duplication process using the selected route within a regulated time is detected, moving any of the duplication process VMs using the selected route to any of the plurality of physical devices from the process device. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating an example of a configuration of a system including a management server according to an example; 
         FIG. 2  is a diagram illustrating an example of a functional configuration of a management server which is an example of a controlling apparatus according to the example; 
         FIG. 3  is a diagram illustrating an example of a data structure of an allowable load quantity table; 
         FIG. 4  is a diagram illustrating an example of a data structure of a correspondence relation table; 
         FIG. 5  is a diagram illustrating an example of a data structure of load information; 
         FIG. 6  is a diagram illustrating an example of a data structure of back-up information; 
         FIG. 7  is a diagram illustrating an example of a data structure of size information; 
         FIG. 8  is a diagram for illustrating an example of a process executed by a management server according to an example; 
         FIGS. 9A and 9B  are flowcharts illustrating a procedure of a controlling process according to an example; 
         FIG. 10  is a flowchart illustrating a procedure of a correspondence relation table generation process according to an example; and 
         FIG. 11  is a diagram illustrating an example of a hardware configuration of a computer which executes a controlling program. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Hereinafter, examples of a management server as an example of a control device disclosed in this specification, a controlling program, and a controlling method are described in detail with reference to the drawings. The examples do not limit the technology disclosed herein. 
     EXAMPLES 
     Example of Configuration of System  1   
       FIG. 1  is a diagram illustrating an example of a configuration of a system  1  including a management server  10  according to an example. As illustrated in the example of  FIG. 1 , the system  1  includes a terminal  5 , the management server  10 , a local area network (LAN) switch  20 , a back-up server  21 , management target servers  22 ,  23 , and  24 , and a fiber channel (FC) switch  25 . The system  1  further includes storage servers  26  and  27 . 
     The terminal  5  is a terminal used by a user such as an operator of the system  1 . The terminal  5 , for example, includes a receiving unit (not illustrated) such as a keyboard or a mouse which receives an instruction from a user, and transmits the received instruction to the management server  10 . As an example of such an instruction, an instruction of performing various settings of a virtual machine is provided. 
     The management server  10  manages various devices of the system  1 . The management server  10 , for example, transmits the instruction of performing various settings of the virtual machine to the management target servers  22  to  24  through the LAN switch  20 . In addition, the management server  10  performs the following process, so that a back-up process, which will be described later, performed by virtual machines  21   a  to  21   d  operated on the back-up server  21  is completed within a regulated time. That is, the management server  10  controls so that the virtual machines  21   a  to  21   d  in which the back-up process is expected not to be completed within the regulated time, are moved to any one management target server among three management target servers  22  to  24 . The management server  10 , for example, transmits a migration instruction for moving the virtual machine in which the back-up process is expected not to be completed within the regulated time, to the management target server, to a VM host  21   e  which performs a control of operating the virtual machines  21   a  to  21   d.    
     The back-up server  21  is connected to the management server  10  through the LAN switch  20 . The back-up server  21  is connected to the storage server  26 . The back-up server  21  is connected to the FC switch  25  through two lines  28   a  and  28   b . Herein, the FC switch  25  is connected to the storage server  27  which is a memory device at a back-up destination of the data obtained by the back-up process. As described above, in the system  1 , there are two routes for connecting the back-up server  21  and the storage server  27  which is a back-up destination of the data obtained by the back-up process. That is, in the system  1 , the routes for connecting the back-up server  21  and the storage server  27  are redundant. Any of the plurality of redundant lines  28   a  and  28   b  may be used in the plurality of virtual machines  21   a  to  21   d.    
     The back-up server  21  includes the virtual machine (VM) host  21   e . The VM host  21   e  is a controlling program of virtualization software which virtually realizes an operation environment of a computer system, and performs a control of operating the virtual machines  21   a  to  21   d . In addition, the VM host  21   e  performs a control of migration of the virtual machines  21   a  to  21   d  among the management target servers  22  to  24 , according to the migration instruction received from the management server  10 . 
     Each of the virtual machines  21   a  to  21   d  executes a back-up program for performing the back-up process of backing up of data in a system area of each virtual machine operated on the management target servers  22  to  24 . The virtual machine  21   a , for example, executes a back-up program A for performing a back-up process of backing up of data in a system area of the virtual machine  22   a  operated on the management target server  22 . The virtual machine  21   b  executes a back-up program B for performing a back-up process of backing up of data in a system area of the virtual machine  22   b  operated on the management target server  22 . The virtual machine  21   c  executes a back-up program C for performing a back-up process of backing up of data in a system area of the virtual machine  23   a  operated on the management target server  23 . The virtual machine  21   d  executes a back-up program D for performing a back-up process of backing up of data in a system area of the virtual machine  24   a  operated on the management target server  24 . Although it will be described later, the back-up process is a process of duplicating data in a system area by storing data in a system area stored in a storage  26   a  to a back-up storage  27   a  which will be described later, and therefore the back-up process is also referred to as a duplication process. In addition, the virtual machines  21   a  to  21   d  which execute the back-up process are an example of the duplication process virtual machine. 
     The management target servers  22  to  24  are devices which are management targets of the management server  10 . In the management target servers  22  to  24 , the virtual machine which executes a predetermined application is operated, and setting of the virtual machine is performed according to an instruction of performing various settings of the virtual machine transmitted from the management server  10 . 
     The management target server  22  includes a VM host  22   c . The VM host  22   c  is a controlling program of virtualization software which virtually realizes an operation environment of a computer system, and performs a control of operating two virtual machines  22   a  and  22   b . In addition, when the VM host  22   c  receives an instruction of performing various settings of the virtual machines  22   a  and  22   b  transmitted from the management server  10 , the VM host  22   c  performs various setting of the virtual machines  22   a  and  22   b  according to the received instructions. The virtual machine  22   a  executes a predetermined application. In addition, the virtual machine  22   a  transmits data in a system area of the virtual machine  22   a  to the storage server  26 . Accordingly, as will be described later, the data in the system area of the virtual machine  22   a  is stored in the storage  26   a  of the storage server  26 . The virtual machine  22   b  executes a predetermined application. The virtual machine  22   b  transmits the data in the system area in the virtual machine  22   b  to the storage server  26 . Accordingly, as will be described later, the data in the system area of the virtual machine  22   b  is stored in the storage  26   a.    
     The management target server  23  includes a VM host  23   c . The VM host  23   c  is a controlling program of virtualization software which virtually realizes an operation environment of a computer system, and performs a control of operating the virtual machine  23   a . In addition, when the VM host  23   c  receives an instruction of performing various settings of the virtual machine  23   a  transmitted from the management server  10 , the VM host performs various setting of the virtual machine  23   a  according to the received instructions. The virtual machine  23   a  executes a predetermined application. In addition, the virtual machine  23   a  transmits data in a system area of the virtual machine  23   a  to the storage server  26 . Accordingly, as will be described later, the data in the system area of the virtual machine  23   a  is stored in the storage  26   a.    
     The management target server  24  includes a VM host  24   c . The VM host  24   c  is a controlling program of virtualization software which virtually realizes an operation environment of a computer system, and performs a control of operating the virtual machine  24   a . In addition, when the VM host  24   c  receives an instruction of performing various settings of the virtual machine  24   a  transmitted from the management server  10 , the VM host performs various setting of the virtual machine  24   a  according to the received instructions. The virtual machine  24   a  executes a predetermined application. In addition, the virtual machine  24   a  transmits data in a system area of the virtual machine  24   a  to the storage server  26 . Accordingly, as will be described later, the data in the system area of the virtual machine  24   a  is stored in the storage  26   a.    
     The FC switch  25  is a relay device which relays data. The FC switch  25  is connected to the back-up server  21  through the lines  28   a  and  28   b  by Fibre Channel fabric. The FC switch  25  is connected to the management target server  22  through a line  28   c , connected to the management target server  23  through a line  28   d , and connected to the management target server  24  through a line  28   e , by Fibre Channel fabric. In addition, the FC switch  25  is connected to the storage server  27  by Fibre Channel fabric. As described above, a storage area network (SAN) is constructed in the system  1 . 
     The storage server  26  includes the storage  26   a  such as a hard disk drive (HDD), and when the storage server receives the data in the system area transmitted from the virtual machines  22   a ,  22   b ,  23   a , and  24   a , the received data in the system area is stored in the storage  26   a . Accordingly, the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is stored in the storage  26   a.    
     The storage server  27  is a memory device at a back-up destination of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a . The storage server  27  includes the back-up storage  27   a  such as an HDD. When the storage server  27  receives the data in the system area of the virtual machine  22   a  transmitted from the virtual machine  21   a  which executes the back-up program A, through the FC switch  25 , the received data is stored in the back-up storage  27   a . When the storage server  27  receives the data in the system area of the virtual machine  22   b  transmitted from the virtual machine  21   b  which executes the back-up program B, through the FC switch  25 , the received data is stored in the back-up storage  27   a . When the storage server  27  receives the data in the system area of the virtual machine  23   a  transmitted from the virtual machine  21   c  which executes the back-up program C, through the FC switch  25 , the received data is stored in the back-up storage  27   a . When the storage server  27  receives the data in the system area of the virtual machine  24   a  transmitted from the virtual machine  21   d  which executes the back-up program D, through the FC switch  25 , the received data is stored in the back-up storage  27   a.    
       FIG. 2  is a diagram illustrating an example of a functional configuration of the management server  10  which is an example of a controlling apparatus according to the example. As illustrated in  FIG. 2 , the management server  10  includes a display unit  11 , a communication unit  12 , a memory unit  13 , and a control unit  14 . 
     The display unit  11  displays various information items. As an example of a device of the display unit  11 , a liquid crystal display or the like is used. 
     When the communication unit  12  receives data such as various instructions transmitted from a device other than the management server  10 , the communication unit transmits the received data to the control unit  14 . When the communication unit  12  receives various data items from the control unit  14 , the communication unit transmits the received data to the designated device. When the control unit  14 , for example, receives an instruction of a user transmitted from the terminal  5 , the control unit transmits the received instruction to the control unit  14 . In addition, when the communication unit  12  receives various instructions to the VM hosts  22   c ,  22   d , and  22   e  transmitted from the control unit  14 , the communication unit transmits the received instructions to the designated VM host. As a device of the communication unit  12 , a network card is used. 
     The memory unit  13  stores various information items. The memory unit  13 , for example, stores an allowable load quantity table  13   a , a correspondence relation table  13   b , load information  13   c , back-up information  13   d , and size information  13   e.    
     The allowable load quantity table  13   a  is a table in which maximum allowable quantities of loads of various resources of each server of the back-up server  21  and the management target servers  22  to  24  are registered.  FIG. 3  is a diagram illustrating an example of a data structure of the allowable load quantity table. The allowable load quantity table  13   a  illustrated in the example of  FIG. 3  includes entries of “physical server name”, “CPU power”, “memory capacity”, and “network band (SAN)”. 
     A name of each server for identifying each server of the back-up server  21  which is a physical server and the management target servers  22  to  24  is registered in the entry of the “physical server name”. As illustrated in  FIG. 3 , a back-up server which is the name of the back-up server  21  is registered in the entry of the “physical server name” in a first record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , a management target server A which is the name of the management target server  22  is registered in the entry of the “physical server name” in a second record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , a management target server B which is the name of the management target server  23  is registered in the entry of the “physical server name” in a third record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , a management target server C which is the name of the management target server  24  is registered in the entry of the “physical server name” in a fourth record of the allowable load quantity table  13   a.    
     An operation frequency and the number of cores indicating process performance of the CPU included by each server of the back-up server  21  and the management target servers  22  to  24  are registered in the entry of the “CPU power”. As illustrated in  FIG. 3 , the operation frequency, 4 GHz, and the number of cores,  32 , of the CPU of the back-up server  21 , the name of which is the back-up server, are registered in the entry of the “CPU power” in the first record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the operation frequency, 4 GHz, and the number of cores,  12 , of the CPU of the management target server  22 , the name of which is the management target server A, are registered in the entry of the “CPU power” in the second record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the operation frequency, 4 GHz, and the number of cores,  24 , of the CPU of the management target server  23 , the name of which is the management target server B, are registered in the entry of the “CPU power” in the third record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the operation frequency, 4 GHz, and the number of cores,  8 , of the CPU of the management target server  24 , the name of which is the management target server C, are registered in the entry of the “CPU power” in the fourth record of the allowable load quantity table  13   a.    
     The capacity items representing the performance of the memory included by each server of the back-up server  21  and the management target servers  22  to  24  are registered in the entry of the “memory capacity”. As illustrated in  FIG. 3 , the capacity of the memory, 128 gigabytes (GB), of the back-up server  21 , the name of which is the back-up server, is registered in the entry of the “memory capacity” in the first record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the capacity of the memory, 32 GB, of the management target server  22 , the name of which is the management target server A, is registered in the entry of the “memory capacity” in the second record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the capacity of the memory, 64 GB, of the management target server  23 , the name of which is the management target server B, is registered in the entry of the “memory capacity” in the third record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the capacity of the memory, 16 GB, of the management target server  24 , the name of which is the management target server C, is registered in the entry of the “memory capacity” in the fourth record of the allowable load quantity table  13   a.    
     Bands of any lines of lines  28   a  to  28   e  connected to each server of the back-up server  21  and the management target servers  22  to  24  are registered in the entry of the “network band (SAN)”. As illustrated in  FIG. 3 , the following content is registered in the entry “network band (SAN)” in the first record of the allowable load quantity table  13   a . That is, the band, 8 gigabits per second (Gbps), of the line  28   a , the name of which is a route  1 , connected to the back-up server  21 , the name of which is the back-up server, is registered. As illustrated in  FIG. 3 , the band, 8 Gbps, of the line  28   b , the name of which is a route  2 , connected to the back-up server  21 , the name of which is the back-up server, is registered in the entry of the “network band (SAN)” in the first record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the band, 8 Gbps, of the line  28   c , the name of which is a route  3 , connected to the management target server  22 , the name of which is the management target server A, is registered in the entry of the “network band (SAN)” in the second record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the band, 8 Gbps, of the line  28   d , the name of which is a route  4 , connected to the management target server  23 , the name of which is the management target server B, is registered in the entry of the “network band (SAN)” in the third record of the allowable load quantity table  13   a . As illustrated in  FIG. 3 , the band, 4 Gbps, of the line  28   e , the name of which is a route  5 , connected to the management target server  24 , the name of which is the management target server C, is registered in the entry of the “network band (SAN)” in the fourth record of the allowable load quantity table  13   a.    
     The description is based on  FIG. 2  again. Correspondences of identifiers of the back-up programs A to D executed by the virtual machines  21   a  to  21   d , and names of the lines used when the virtual machines  21   a  to  21   d  execute the back-up programs A to D, are registered in the correspondence relation table  13   b .  FIG. 4  is a diagram illustrating an example of a data structure of the correspondence relation table. The correspondence relation table  13   b  illustrated in the example of  FIG. 4  includes entries of a “back-up program” and a “network route (SAN)”. 
     The identifiers of the back-up programs A to D executed by the virtual machines  21   a  to  21   d  are registered in the entry of the “back-up program” by the control unit  14 . As illustrated in  FIG. 4 , an identifier A of the back-up program A executed by the virtual machine  21   a  is registered in the entry of the “back-up program” in a first record of the correspondence relation table  13   b . As illustrated in  FIG. 4 , an identifier B of the back-up program B executed by the virtual machine  21   b  is registered in the entry of the “back-up program” in a second record of the correspondence relation table  13   b . As illustrated in  FIG. 4 , an identifier C of the back-up program C executed by the virtual machine  21   c  is registered in the entry of the “back-up program” in a third record of the correspondence relation table  13   b . As illustrated in  FIG. 4 , an identifier D of the back-up program D executed by the virtual machine  21   d  is registered in the entry of the “back-up program” in a fourth record of the correspondence relation table  13   b.    
     The names of the lines used when the virtual machines  21   a  to  21   d  for executing the back-up programs A to D execute the back-up programs A to D, are registered in the entry of the “network route (SAN)” by the control unit  14 . As illustrated in  FIG. 4 , the route  1  which is the name of the line  28   a  is registered in the entry of the “network route (SAN)” in the first record of the correspondence relation table  13   b . As illustrated in  FIG. 4 , the route  2  which is the name of the line  28   b  is registered in the entry of the “network route (SAN)” in the second record of the correspondence relation table  13   b . As illustrated in  FIG. 4 , the route  1  which is the name of the line  28   a  is registered in the entry of the “network route (SAN)” in the third record of the correspondence relation table  13   b . As illustrated in  FIG. 4 , the route  2  which is the name of the line  28   b  is registered in the entry of the “network route (SAN)” in the fourth record of the correspondence relation table  13   b.    
     That is, the first record of the correspondence relation table  13   b  illustrated in the example of  FIG. 4  indicates that the virtual machine  21   a  for executing the back-up program A, the identifier of which is A, uses the line  28   a , the name of which is the route  1 , when executing the back-up program A. The second record of the correspondence relation table  13   b  illustrated in the example of  FIG. 4  indicates that the virtual machine  21   b  for executing the back-up program B, the identifier of which is B, uses the line  28   b , the name of which is the route  2 , when executing the back-up program B. The third record of the correspondence relation table  13   b  illustrated in the example of  FIG. 4  indicates that the virtual machine  21   c  for executing the back-up program C, the identifier of which is C, uses the line  28   a , the name of which is the route  1 , when executing the back-up program C. The fourth record of the correspondence relation table  13   b  illustrated in the example of  FIG. 4  indicates that the virtual machine  21   d  for executing the back-up program D, the identifier of which is D, uses the line  28   b , the name of which is the route  2 , when executing the back-up program D. 
     The description is based on  FIG. 2  again. The loads of various resources when the virtual machines  21   a  to  21   d  execute the back-up programs A to D are registered in the load information  13   c .  FIG. 5  is a diagram illustrating an example of a data structure of the load information. The load information  13   c  illustrated in the example of  FIG. 5  includes entries of a “back-up program”, a “CPU load (%)”, a “memory load (%)”, and a “load of SAN (%)”. 
     The identifiers of the back-up programs A to D executed by the virtual machines  21   a  to  21   d  are registered in the entry of the “back-up program” by the control unit  14 . As illustrated in  FIG. 5 , the identifier A of the back-up program A executed by the virtual machine  21   a  is registered in the entry of the “back-up program” in a first record of the load information  13   c . As illustrated in  FIG. 5 , the identifier B of the back-up program B executed by the virtual machine  21   b  is registered in the entry of the “back-up program” in a second record of the load information  13   c . As illustrated in  FIG. 5 , the identifier C of the back-up program C executed by the virtual machine  21   c  is registered in the entry of the “back-up program” in a third record of the load information  13   c . As illustrated in  FIG. 5 , the identifier D of the back-up program D executed by the virtual machine  21   d  is registered in the entry of the “back-up program” in a fourth record of the load information  13   c.    
     The loads of the CPU of the virtual machines  21   a  to  21   d  when the virtual machines  21   a  to  21   d  execute the back-up programs A to D are registered in the entry of the “CPU load (%)” by the control unit  14 . For example, average loads (%) of the CPU which will be described later are registered in the entry of the “CPU load (%)” by the control unit  14 . An average load, 10%, of the CPU which will be described later is registered in the entry of the “CPU load (%)” in the first record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 20%, of the CPU which will be described later is registered in the entry of the “CPU load (%)” in the second record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 30%, of the CPU which will be described later is registered in the entry of the “CPU load (%)” in the third record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 10%, of the CPU which will be described later is registered in the entry of the “CPU load (%)” in the fourth record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . 
     The loads of the memory of the virtual machines  21   a  to  21   d  when the virtual machines  21   a  to  21   d  execute the back-up programs A to D are registered in the entry of the “memory load (%)” by the control unit  14 . For example, average loads (%) of the memory which will be described later are registered in the entry of the “memory load (%)” by the control unit  14 . An average load, 20%, of the memory which will be described later is registered in the entry of the “memory load (%)” in the first record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 20%, of the memory which will be described later is registered in the entry of the “memory load (%)” in the second record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 30%, of the memory which will be described later is registered in the entry of the “memory load (%)” in the third record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 20%, of the memory which will be described later is registered in the entry of the “memory load (%)” in the fourth record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . 
     The average loads (%) of the lines due to the virtual machine which will be described later are registered in the entry of the “load of SAN (%)” by the control unit  14 . An average load, 10 (%), of the line  28   a  due to the virtual machine  21   a  which will be described later is registered in the entry of the “load of SAN (%)” in the first record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 5 (%), of the line  28   b  due to the virtual machine  21   b  which will be described later is registered in the entry of the “load of SAN (%)” in the second record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 30 (%), of the line  28   a  due to the virtual machine  21   c  which will be described later is registered in the entry of the “load of SAN (%)” in the third record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . An average load, 95 (%), of the line  28   b  due to the virtual machine  21   d  which will be described later is registered in the entry of the “load of SAN (%)” in the fourth record of the load information  13   c  illustrated in the example of  FIG. 5 , by the control unit  14 . 
     The description is based on  FIG. 2  again. Days and time zones when the back-up processes of the data in the system areas of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  are performed are registered in the back-up information  13   d.    
       FIG. 6  is a diagram illustrating an example of a data structure of the back-up information. 
     The back-up information  13   d  illustrated in the example of  FIG. 6  includes entries of a “day” and a “back-up time zone”. The information items indicating any one of Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, and Sunday are registered in the entry of the “day”. For example, as illustrated in  FIG. 6 , “Mon” indicating Monday is registered in the entry of the “day” in a first record of the back-up information  13   d . As illustrated in  FIG. 6 , “Tue” indicating Tuesday is registered in the entry of the “day” in a second record of the back-up information  13   d . As illustrated in  FIG. 6 , “Wed” indicating Wednesday is registered in the entry of the “day” in a third record of the back-up information  13   d . As illustrated in  FIG. 6 , “Thu” indicating Thursday is registered in the entry of the “day” in a fourth record of the back-up information  13   d . As illustrated in  FIG. 6 , “Fri” indicating Friday is registered in the entry of the “day” in a fifth record of the back-up information  13   d . As illustrated in  FIG. 6 , “Sat” indicating Saturday is registered in the entry of the “day” in a sixth record of the back-up information  13   d . As illustrated in  FIG. 6 , “Sun” indicating Sunday is registered in the entry of the “day” in a seventh record of the back-up information  13   d.    
     In addition, the time zones of the back-up processes are registered in the entry of the “back-up time zone”. For example, as illustrated in  FIG. 6 , a time zone of the back-up process from 12:00 am to 5:00 am is registered in the entry of the “back-up time zone” in the first record of the back-up information  13   d . As illustrated in  FIG. 6 , a time zone of the back-up process from 2:00 am to 5:00 am is registered in the entry of the “back-up time zone” in the second record of the back-up information  13   d . As illustrated in  FIG. 6 , a time zone of the back-up process from 2:00 am to 5:00 am and a time zone of the back-up process from 10:00 pm to 12:00 am are registered in the entry of the “back-up time zone” in the third record of the back-up information  13   d . As illustrated in  FIG. 6 , a time zone of the back-up process from 12:00 am to 5:00 am is registered in the entry of the “back-up time zone” in the fourth record of the back-up information  13   d . As illustrated in  FIG. 6 , a time zone of the back-up process from 2:00 am to 5:00 am is registered in the entry of the “back-up time zone” in the fifth record of the back-up information  13   d . As illustrated in  FIG. 6 , a time zone of the back-up process from 4:00 am to 7:00 am and a time zone of the back-up process from 9:00 pm to 12:00 am are registered in the entry of the “back-up time zone” in the sixth record of the back-up information  13   d . As illustrated in  FIG. 6 , a time zone of the back-up process from 12:00 am to 7:00 am and a time zone of the back-up process from 9:00 pm to 12:00 am are registered in the entry of the “back-up time zone” in the seventh record of the back-up information  13   d.    
     That is, the first record of the back-up information  13   d  illustrated in the example of  FIG. 6  indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Monday within the regulated time from 12:00 am to 5:00 am. The second record of the back-up information  13   d  illustrated in the example of  FIG. 6  indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Tuesday within the regulated time from 2:00 am to 5:00 am. The third record of the back-up information  13   d  illustrated in the example of  FIG. 6  indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Wednesday within the regulated time from 2:00 am to 5:00 am. The third record of the back-up information  13   d  illustrated in the example of  FIG. 6  also indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Wednesday within the regulated time from 10:00 pm to 12:00 am. The fourth record of the back-up information  13   d  illustrated in the example of  FIG. 6  indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Thursday within the regulated time from 12:00 am to 5:00 am. The fifth record of the back-up information  13   d  illustrated in the example of  FIG. 6  indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Friday within the regulated time from 2:00 am to 5:00 am. The sixth record of the back-up information  13   d  illustrated in the example of  FIG. 6  indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Saturday within the regulated time from 4:00 am to 7:00 am. The sixth record of the back-up information  13   d  illustrated in the example of  FIG. 6  also indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Saturday within the regulated time from 9:00 pm to 12:00 am. The seventh record of the back-up information  13   d  illustrated in the example of  FIG. 6  indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Sunday within the regulated time from 12:00 am to 7:00 am. The seventh record of the back-up information  13   d  illustrated in the example of  FIG. 6  also indicates that the back-up process of the data in the system area of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  is performed on Sunday within the regulated time from 9:00 pm to 12:00 am. 
     The description is based on  FIG. 2  again. Names of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  and sizes of data items in the system areas of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  are registered in the size information  13   e.    
       FIG. 7  is a diagram illustrating an example of a data structure of the size information. The size information  13   e  illustrated in the example of  FIG. 7  includes entries of a “virtual machine name of back-up target” and a “size of data in system area”. Names of the virtual machines of any of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  are registered in the entry of the “virtual machine name of back-up target”. For example, as illustrated in  FIG. 7 , an operation A which is the name of the virtual machine  22   a  is registered in the entry of the “virtual machine name of back-up target” in a first record of the size information  13   e . As illustrated in  FIG. 7 , an operation B which is the name of the virtual machine  22   b  is registered in the entry of the “virtual machine name of back-up target” in a second record of the size information  13   e . As illustrated in  FIG. 7 , an operation C which is the name of the virtual machine  23   a  is registered in the entry of the “virtual machine name of back-up target” in a third record of the size information  13   e . As illustrated in  FIG. 7 , an operation D which is the name of the virtual machine  24   a  is registered in the entry of the “virtual machine name of back-up target” in a fourth record of the size information  13   e.    
     Sizes of the data items in the system areas of the virtual machines  22   a ,  22   b ,  23   a , and  24   a  which are back-up targets are registered in the entry of the “size of data in system area”. For example, as illustrated in  FIG. 7 , a size, 20 GB, of the data in the system area of the virtual machine  22   a , the name of which is the operation A, is registered in the entry of the “size of data in system area” in the first record of the size information  13   e . As illustrated in  FIG. 7 , a size, 30 GB, of the data in the system area of the virtual machine  22   b , the name of which is the operation B, is registered in the entry of the “size of data in system area” in the second record of the size information  13   e . As illustrated in  FIG. 7 , a size, 10 GB, of the data in the system area of the virtual machine  23   a , the name of which is the operation C, is registered in the entry of the “size of data in system area” in the third record of the size information  13   e . As illustrated in  FIG. 7 , a size, 50 GB, of the data in the system area of the virtual machine  24   a , the name of which is the operation D, is registered in the entry of the “size of data in system area” in the fourth record of the size information  13   e.    
     The memory unit  13  is, for example, a semiconductor memory element such as a flash memory or a memory device such as a hard disk or an optical disk. 
     By returning to the description of  FIG. 2 , the control unit  14  includes an internal memory for storing programs or control data items for regulating various process procedures, and executes various processes with the programs and data items. As illustrated in  FIG. 2 , the control unit  14  includes an acquisition unit  14   a , a first specifying unit  14   b , a second specifying unit  14   c , and a movement control unit  14   d.    
     The acquisition unit  14   a  acquires band loads of the plurality of lines  28   a  and  28   b , resource usages of the plurality of management target servers  22  to  24 , and percentages of completion indicating a degree of completion of the back-up process executed by the plurality of virtual machines  21   a  to  21   d.    
     An embodiment of the acquisition unit  14   a  will be described. The acquisition unit  14   a  determines whether or not the current time is in the time zone for performing the back-up process registered in the back-up information  13   d  at predetermined time intervals (for example, at every 30 seconds), with reference to the back-up information  13   d.    
     When it is determined that the current time is in the time zone for performing the back-up process registered in the back-up information  13   d , that is, when it is determined that the current time is in the time zone when the virtual machines  21   a  to  21   d  perform the back-up process, the acquisition unit  14   a  performs the following process. That is, the acquisition unit  14   a  acquires maximum allowable quantities of the loads of various resources (CPU, memory, and lines connected to each server) of each server of the back-up server  21  and the management target servers  22  to  24  from the allowable load quantity table  13   a . For example, when the allowable load quantity table  13   a  illustrated in the example of  FIG. 3  is stored in the memory unit  13 , the acquisition unit  14   a  performs the following process. That is, the acquisition unit  14   a  specifies the record in which the back-up server is registered in the entry of the “physical server name”, and acquires the operation frequency, 4 GHz, and the number of cores,  32 , registered in the entry of the “CPU power” of the specified record, as the maximum allowable quantities of the load of the CPU of the back-up server  21 . The acquisition unit  14   a  acquires the capacity of the memory, 128 GB, registered in the entry of the “memory capacity” of the specified record, as the maximum allowable quantity of the load of the memory of the back-up server  21 . The acquisition unit  14   a  acquires the band, 8 Gbps, of the line  28   a , the name of which is the route  1  and the band, 8 Gbps, of the line  28   b , the name of which is the route  2 , registered in the entry of the “network band (SAN)” of the specified record, as the following values. That is, the acquisition unit  14   a  acquires the band, 8 Gbps, of the line  28   a , the name of which is the route  1  and the band, 8 Gbps, of the line  28   b , the name of which is the route  2 , as the maximum allowable quantities of the loads of the lines connected to the back-up server  21 . 
     In addition, the acquisition unit  14   a  specifies the record in which the management target server A is registered in the entry of the “physical server name”. The acquisition unit  14   a  acquires the operation frequency, 4 GHz, and the number of cores,  12 , of the CPU as the maximum allowable quantities of the load of the CPU of the management target server  22 , by performing the same process as the process described above with respect to the specified record. The acquisition unit  14   a  acquires the capacity of the memory, 32 GB, as the maximum allowable quantity of the load of the memory of the management target server  22 , by performing the same process as the process described above with respect to the specified record. The acquisition unit  14   a  acquires the band, 8 Gbps, of the line  28   c , the name of which is the route  3 , as the maximum allowable quantity of the load of the line connected to the management target server  22 , by performing the same process as the process described above with respect to the specified record. 
     In addition, the acquisition unit  14   a  specifies the record in which the management target server B is registered in the entry of the “physical server name”. The acquisition unit  14   a  acquires the operation frequency, 4 GHz, and the number of cores,  24 , of the CPU as the maximum allowable quantities of the load of the CPU of the management target server  23 , by performing the same process as the process described above with respect to the specified record. The acquisition unit  14   a  acquires the capacity of the memory, 64 GB, as the maximum allowable quantity of the load of the memory of the management target server  23 , by performing the same process as the process described above with respect to the specified record. The acquisition unit  14   a  acquires the band, 8 Gbps, of the line  28   d , the name of which is the route  4 , as the maximum allowable quantity of the load of the line connected to the management target server  23 , by performing the same process as the process described above with respect to the specified record. 
     In addition, the acquisition unit  14   a  specifies the record in which the management target server C is registered in the entry of the “physical server name”. The acquisition unit  14   a  acquires the operation frequency, 4 GHz, and the number of cores,  8 , of the CPU as the maximum allowable quantities of the load of the CPU of the management target server  24 , by performing the same process as the process described above with respect to the specified record. The acquisition unit  14   a  acquires the capacity of the memory, 16 GB, as the maximum allowable quantity of the load of the memory of the management target server  24 , by performing the same process as the process described above with respect to the specified record. The acquisition unit  14   a  acquires the band, 4 Gbps, of the line  28   e , the name of which is the route  5 , as the maximum allowable quantity of the load of the line connected to the management target server  24 , by performing the same process as the process described above with respect to the specified record. 
     With the method described above, the acquisition unit  14   a  acquires the maximum allowable quantities of the loads of the various resources of servers of the back-up server  21  and the management target servers  22  to  24 , from the allowable load quantity table  13   a.    
     Next, the acquisition unit  14   a  registers various information items in the correspondence relation table  13   b  and executes a correspondence relation table generation process of generating the correspondence relation table  13   b . In the correspondence relation table generation process, the acquisition unit  14   a , first, calculates the total of maximum bands of the lines  28   a  and  28   b  connected to the back-up server  21 . The acquisition unit  14   a , for example, calculates the total of the bands of the lines  28   a  and  28   b  previously acquired. When the allowable load quantity table  13   a  illustrated in the example of  FIG. 3  is stored in the memory unit  13 , the acquisition unit  14   a  calculates the total of the bands, 16 Gbps ((8+8) Gbps) of the lines  28   a  and  28   b.    
     In the correspondence relation table generation process, the acquisition unit  14   a  calculates each rate of the bands of the lines  28   a  and  28   b  with respect to the calculated total of the bands. When the allowable load quantity table  13   a  illustrated in the example of  FIG. 3  is stored in the memory unit  13 , the acquisition unit  14   a  calculates 8/16 as a rate of the band of the line  28   a  with respect to the total. In addition, the acquisition unit  14   a  calculates 8/16 as a rate of the band of the line  28   b  with respect to the total. 
     In the correspondence relation table generation process, the acquisition unit  14   a  specifies the virtual machine for executing the back-up process. For example, as illustrated in  FIG. 1 , when four virtual machines  21   a  to  21   d  execute the back-up process, the acquisition unit  14   a  specifies the virtual machines  21   a  to  21   d  for executing the back-up process. 
     In the correspondence relation table generation process, the acquisition unit  14   a  selects all of the specified virtual machines one by one. Every time the virtual machine is selected, the acquisition unit  14   a  associates the selected machine with the lines  28   a  and  28   b , according to the calculated rate. For example, when 8/16 is calculated as the rate of the band of the line  28   a  with respect to the total and 8/16 is calculated as the rate of the band of the line  28   b  with respect to the total, the acquisition unit  14   a  performs the following process. That is, the acquisition unit  14   a  associates the virtual machine selected with a possibility of 50% with respect to the line  28   a  and 50% with respect to the line  28   b  with any line of the line  28   a  and line  28   b . Accordingly, the lines are associated with respect to all of the specified virtual machines. 
     In the correspondence relation table generation process, the acquisition unit  14   a  registers the association of the virtual machines and the lines in the correspondence relation table  13   b . For example, when the virtual machines  21   a  and  21   c  are associated with the line  28   a  and the virtual machines  21   b  and  21   d  are associated with the line  28   b , the acquisition unit  14   a  performs the following process. That is, as previously illustrated in  FIG. 4 , the acquisition unit  14   a  registers the identifier A of the back-up program A executed by the virtual machine  21   a  in the entry of the “back-up program” of the correspondence relation table  13   b . The acquisition unit  14   a  registers the route  1  which is the name of the line  28   a , in the entry of the “network route (SAN)” of the record in which the identifier A is registered in the entry of the “back-up program”. As previously illustrated in  FIG. 4 , the acquisition unit  14   a  registers the identifier B of the back-up program B executed by the virtual machine  21   b  in the entry of the “back-up program” of the correspondence relation table  13   b . The acquisition unit  14   a  registers the route  2  which is the name of the line  28   b , in the entry of the “network route (SAN)” of the record in which the identifier B is registered in the entry of the “back-up program”. As previously illustrated in  FIG. 4 , the acquisition unit  14   a  registers the identifier C of the back-up program C executed by the virtual machine  21   c  in the entry of the “back-up program” of the correspondence relation table  13   b . The acquisition unit  14   a  registers the route  1  which is the name of the line  28   a , in the entry of the “network route (SAN)” of the record in which the identifier C is registered in the entry of the “back-up program”. As previously illustrated in  FIG. 4 , the acquisition unit  14   a  registers the identifier D of the back-up program D executed by the virtual machine  21   d  in the entry of the “back-up program” of the correspondence relation table  13   b . The acquisition unit  14   a  registers the route  2  which is the name of the line  28   b , in the entry of the “network route (SAN)” of the record in which the identifier D is registered in the entry of the “back-up program”. 
     As described above, the correspondence relation table  13   b  is generated by executing the correspondence relation table generation process. 
     When the correspondence relation table  13   b  is generated, the acquisition unit  14   a  controls so that the virtual machines  21   a  to  21   d  start the back-up process. For example, when the correspondence relation table  13   b  is generated, the acquisition unit  14   a  transmits an instruction of causing the virtual machine  21   a  to execute the back-up program A, to the VM host  21   e . The VM host  21   e  which received such an instruction transmits the instruction of executing the back-up program A to the virtual machine  21   a . The virtual machine  21   a  which received the instruction of executing the back-up program A, executes the back-up program A according to the instruction. That is, the virtual machine  21   a  executes the back-up process. In the back-up process, the virtual machine  21   a  acquires data in the system area of the virtual machine  22   a  from the storage  26   a  of the storage server  26 , and transmits the acquired data in the system area to the storage server  27  through the line  28   a  and the FC switch  25 . Therefore, the data in the system area of the virtual machine  22   a  is stored in the back-up storage  27   a , and the data in the system area of the virtual machine  22   a  is duplicated. 
     When the correspondence relation table  13   b  is generated, the acquisition unit  14   a  transmits an instruction of causing the virtual machine  21   b  to execute the back-up program B, to the VM host  21   e . The VM host  21   e  which received such an instruction transmits the instruction of executing the back-up program B to the virtual machine  21   b . The virtual machine  21   b  which received the instruction of executing the back-up program B, executes the back-up program B according to the instruction. That is, the virtual machine  21   b  executes the back-up process. In the back-up process, the virtual machine  21   b  acquires data in the system area of the virtual machine  22   b  from the storage  26   a  of the storage server  26 , and transmits the acquired data in the system area to the storage server  27  through the line  28   b  and the FC switch  25 . Therefore, the data in the system area of the virtual machine  22   b  is stored in the back-up storage  27   a , and the data in the system area of the virtual machine  22   b  is duplicated. 
     When the correspondence relation table  13   b  is generated, the acquisition unit  14   a  transmits an instruction of causing the virtual machine  21   c  to execute the back-up program C, to the VM host  21   e . The VM host  21   e  which received such an instruction transmits the instruction of executing the back-up program C to the virtual machine  21   c . The virtual machine  21   c  which received the instruction of executing the back-up program C, executes the back-up program C according to the instruction. That is, the virtual machine  21   c  executes the back-up process. In the back-up process, the virtual machine  21   c  acquires data in the system area of the virtual machine  23   a  from the storage  26   a  of the storage server  26 , and transmits the acquired data in the system area to the storage server  27  through the line  28   a  and the FC switch  25 . Therefore, the data in the system area of the virtual machine  23   a  is stored in the back-up storage  27   a , and the data in the system area of the virtual machine  23   a  is duplicated. 
     When the correspondence relation table  13   b  is generated, the acquisition unit  14   a  transmits an instruction of causing the virtual machine  21   d  to execute the back-up program D, to the VM host  21   e . The VM host  21   e  which received such an instruction transmits the instruction of executing the back-up program D to the virtual machine  21   d . The virtual machine  21   d  which received the instruction of executing the back-up program D, executes the back-up program D according to the instruction. That is, the virtual machine  21   d  executes the back-up process. In the back-up process, the virtual machine  21   d  acquires data in the system area of the virtual machine  24   a  from the storage  26   a  of the storage server  26 , and transmits the acquired data in the system area to the storage server  27  through the line  28   b  and the FC switch  25 . Therefore, the data in the system area of the virtual machine  24   a  is stored in the back-up storage  27   a , and the data in the system area of the virtual machine  24   a  is duplicated. 
     The acquisition unit  14   a  starts the measurement of the loads of various resources when the virtual machines  21   a  to  21   d  execute the back-up programs A to D. The acquisition unit  14   a  registers the measured loads of various resources to the load information  13   c . The acquisition unit  14   a , for example, starts measuring the usages (GHz) of the CPU of the virtual machine  21   a  which executes the back-up program A, at predetermined time intervals (for example, at every 3 seconds). The acquisition unit  14   a  performs the following process each time when measuring the usage (GHz) of the CPU. That is, the acquisition unit  14   a  calculates an average value of the usages of the CPU measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value by the operation frequency, 4 GHz, of the CPU of the back-up server  21 , as an average load (%) of the CPU of the virtual machine  21   a . For example, when the average value of the usages of the CPU of the virtual machine  21   a  measured within the last 5 minutes from the current time is 0.4 GHz, the acquisition unit  14   a  calculates the average load of the CPU of the virtual machine  21   a  as 10%. The acquisition unit  14   a  associates the average load with the identifier A of the back-up program A and overwrites and registers the average load of the CPU of the virtual machine  21   a  in the load information  13   c.    
     The acquisition unit  14   a  starts measuring the usages (GHz) of the CPU of the virtual machine  21   b  which executes the back-up program B, at predetermined time intervals (for example, at every 3 seconds). The acquisition unit  14   a  performs the following process each time when measuring the usage (GHz) of the CPU. That is, the acquisition unit  14   a  calculates an average value of the usages of the CPU measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value by the operation frequency, 4 GHz, of the CPU of the back-up server  21 , as an average load (%) of the CPU of the virtual machine  21   b . The acquisition unit  14   a  associates the average load with the identifier B of the back-up program B and overwrites and registers the average load of the CPU of the virtual machine  21   b  in the load information  13   c.    
     The acquisition unit  14   a  starts measuring the usages (GHz) of the CPU of the virtual machine  21   c  which executes the back-up program C, at predetermined time intervals (for example, at every 3 seconds). The acquisition unit  14   a  performs the following process each time when measuring the usage (GHz) of the CPU. That is, the acquisition unit  14   a  calculates an average value of the usages of the CPU measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value by the operation frequency, 4 GHz, of the CPU of the back-up server  21 , as an average load (%) of the CPU of the virtual machine  21   c . The acquisition unit  14   a  associates the average load with the identifier C of the back-up program C and overwrites and registers the average load of the CPU of the virtual machine  21   c  in the load information  13   c.    
     The acquisition unit  14   a  starts measuring the usages (GHz) of the CPU of the virtual machine  21   d  which executes the back-up program D, at predetermined time intervals (for example, at every 3 seconds). The acquisition unit  14   a  performs the following process each time when measuring the usage (GHz) of the CPU. That is, the acquisition unit  14   a  calculates an average value of the usages of the CPU measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value by the operation frequency, 4 GHz, of the CPU of the back-up server  21 , as an average load (%) of the CPU of the virtual machine  21   d . The acquisition unit  14   a  associates the average load with the identifier D of the back-up program D and overwrites and registers the average load of the CPU of the virtual machine  21   d  in the load information  13   c.    
     The acquisition unit  14   a  starts measuring the usages (GB) of the memory of the virtual machine  21   a  which executes the back-up program A, at predetermined time intervals (for example, at every 3 seconds). The acquisition unit  14   a  performs the following process each time when measuring the usage (GB) of the memory. That is, the acquisition unit  14   a  calculates an average value of the usages of the memory measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value by the capacity, 128 GB, of the memory of the back-up server  21 , as an average load (%) of the memory of the virtual machine  21   a . For example, when the average value of the usages of the memory of the virtual machine  21   a  measured within the last 5 minutes from the current time is 25.6 GB, the acquisition unit  14   a  calculates the average load of the memory of the virtual machine  21   a  as 20%. The acquisition unit  14   a  associates the average load with the identifier A of the back-up program A and overwrites and registers the average load of the memory of the virtual machine  21   a  in the load information  13   c.    
     The acquisition unit  14   a  starts measuring the usages (GB) of the memory of the virtual machine  21   b  which executes the back-up program B, at predetermined time intervals (for example, at every 3 seconds). The acquisition unit  14   a  performs the following process each time when measuring the usage (GB) of the memory. That is, the acquisition unit  14   a  calculates an average value of the usages of the memory measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value by the capacity, 128 GB, of the memory of the back-up server  21 , as an average load (%) of the memory of the virtual machine  21   b . The acquisition unit  14   a  associates the average load with the identifier B of the back-up program B and overwrites and registers the average load of the memory of the virtual machine  21   b  in the load information  13   c.    
     The acquisition unit  14   a  starts measuring the usages (GB) of the memory of the virtual machine  21   c  which executes the back-up program C, at predetermined time intervals (for example, at every 3 seconds). The acquisition unit  14   a  performs the following process each time when measuring the usage (GB) of the memory. That is, the acquisition unit  14   a  calculates an average value of the usages of the memory measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value by the capacity, 128 GB, of the memory of the back-up server  21 , as an average load (%) of the memory of the virtual machine  21   c . The acquisition unit  14   a  associates the average load with the identifier C of the back-up program C and overwrites and registers the average load of the memory of the virtual machine  21   c  in the load information  13   c.    
     The acquisition unit  14   a  starts measuring the usages (GB) of the memory of the virtual machine  21   d  which executes the back-up program D, at predetermined time intervals (for example, at every 3 seconds). The acquisition unit  14   a  performs the following process each time when measuring the usage (GB) of the memory. That is, the acquisition unit  14   a  calculates an average value of the usages of the memory measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value by the capacity, 128 GB, of the memory of the back-up server  21 , as an average load (%) of the memory of the virtual machine  21   d . The acquisition unit  14   a  associates the average load with the identifier D of the back-up program D and overwrites and registers the average load of the memory of the virtual machine  21   d  in the load information  13   c.    
     The acquisition unit  14   a  performs the following process at predetermined time intervals (for example, at every 3 seconds). For example, the acquisition unit  14   a  starts measuring data quantity (Gbps) of the back-up target data flowing, for 1 second, to the line  28   a  used when the virtual machine  21   a  for executing the back-up program A executes the back-up process. Herein, the back-up target data indicates data in the system area of the virtual machine  22   a . The acquisition unit  14   a  performs the following process each time when measuring the data quantity. That is, the acquisition unit  14   a  calculates an average value of the data quantities measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value of the data quantities by the band, 8 Gbps, of the line  28   a , as an average load (%) of the line  28   a  due to the virtual machine  21   a . For example, when the average value of the data quantities of the back-up target data measured within the last 5 minutes from the current time for 1 second is 0.8 Gbps, the acquisition unit  14   a  calculates the average load of the line  28   a  due to the virtual machine  21   a  as 10%. The acquisition unit  14   a  associates the average load with the identifier A of the back-up program A and overwrites and registers the average load of the line  28   a  due to the virtual machine  21   a  in the load information  13   c.    
     The acquisition unit  14   a  performs the following process at predetermined time intervals (for example, at every 3 seconds). For example, the acquisition unit  14   a  starts measuring data quantity (Gbps) of the back-up target data flowing, for 1 second, to the line  28   b  used when the virtual machine  21   b  for executing the back-up program B executes the back-up process. Herein, the back-up target data indicates data in the system area of the virtual machine  22   b . The acquisition unit  14   a  performs the following process each time when measuring the data quantity. That is, the acquisition unit  14   a  calculates an average value of the data quantities measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value of the data quantities by the band, 8 Gbps, of the line  28   b , as an average load (%) of the line  28   b  due to the virtual machine  21   b . The acquisition unit  14   a  associates the average load with the identifier B of the back-up program B and overwrites and registers the average load of the line  28   b  due to the virtual machine  21   b  in the load information  13   c.    
     The acquisition unit  14   a  performs the following process at predetermined time intervals (for example, at every 3 seconds). For example, the acquisition unit  14   a  starts measuring data quantity (Gbps) of the back-up target data flowing, for 1 second, to the line  28   a  used when the virtual machine  21   c  for executing the back-up program C executes the back-up process. Herein, the back-up target data indicates data in the system area of the virtual machine  23   a . The acquisition unit  14   a  performs the following process each time when measuring the data quantity. That is, the acquisition unit  14   a  calculates an average value of the data quantities measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value of the data quantities by the band, 8 Gbps, of the line  28   a , as an average load (%) of the line  28   a  due to the virtual machine  21   c . The acquisition unit  14   a  associates the average load with the identifier C of the back-up program C and overwrites and registers the average load of the line  28   a  due to the virtual machine  21   c  in the load information  13   c.    
     The acquisition unit  14   a  performs the following process at predetermined time intervals (for example, at every 3 seconds). For example, the acquisition unit  14   a  starts measuring data quantity (Gbps) of the back-up target data flowing, for 1 second, to the line  28   b  used when the virtual machine  21   d  for executing the back-up program D executes the back-up process. Herein, the back-up target data indicates data in the system area of the virtual machine  24   a . The acquisition unit  14   a  performs the following process each time when measuring the data quantity. That is, the acquisition unit  14   a  calculates an average value of the data quantities measured within the last 5 minutes from the current time, and calculates a value obtained by multiplying 100 by a value obtained by dividing the calculated average value of the data quantities by the band, 8 Gbps, of the line  28   b , as an average load (%) of the line  28   b  due to the virtual machine  21   d . The acquisition unit  14   a  associates the average load with the identifier D of the back-up program D and overwrites and registers the average load of the line  28   b  due to the virtual machine  21   d  in the load information  13   c.    
     With the method described above, the acquisition unit  14   a  starts measuring the loads of various resources when the virtual machines  21   a  to  21   d  execute the back-up programs A to D, and starts updating the loads of various resources in the load information  13   c.    
     In addition, when it is determined that the first specifying unit  14   b  which will be described later determines that there is an average load exceeding a predetermined value (for example, 90%) among various average loads registered in the load information  13   c , the acquisition unit  14   a  performs the following process. That is, the acquisition unit  14   a  acquires the sizes of the data items in the system areas of the virtual machines  22   a ,  22   b ,  23   a , and  24   a , from the size information  13   e . Next, the acquisition unit  14   a  specifies the data quantity of the data in the system area of the virtual machine  22   a  which has been transmitted to the storage  27 . The acquisition unit  14   a  calculates a value obtained by multiplying 100 by a value obtained by dividing the specified data quantity by the size of the data in the system area of the virtual machine  22   a , as the percentage of completion (%) of the back-up process of the virtual machine  21   a . Next, the acquisition unit  14   a  specifies the data quantity of the data in the system area of the virtual machine  22   b  which has been transmitted to the storage  27 . The acquisition unit  14   a  calculates a value obtained by multiplying 100 by a value obtained by dividing the specified data quantity by the size of the data in the system area of the virtual machine  22   b , as the percentage of completion (%) of the back-up process of the virtual machine  21   b . Next, the acquisition unit  14   a  specifies the data quantity of the data in the system area of the virtual machine  23   a  which has been transmitted to the storage  27 . The acquisition unit  14   a  calculates a value obtained by multiplying 100 by a value obtained by dividing the specified data quantity by the size of the data in the system area of the virtual machine  23   a , as the percentage of completion (%) of the back-up process of the virtual machine  21   c . Next, the acquisition unit  14   a  specifies the data quantity of the data in the system area of the virtual machine  24   a  which has been transmitted to the storage  27 . The acquisition unit  14   a  calculates a value obtained by multiplying 100 by a value obtained by dividing the specified data quantity by the size of the data in the system area of the virtual machine  24   a , as the percentage of completion (%) of the back-up process of the virtual machine  21   d . The percentage of completion of the back-up process is a value indicating a degree of completion of the back-up process. By doing so, the acquisition unit  14   a  acquires the percentages of completion of the back-up process. 
     When an increase of at least one used band of the plurality of lines  28   a  and  28   b  is detected and delay of the back-up process using the line with the detected increase of the used band is detected, the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  specifies any virtual machine which performs the back-up process by using the line with the detected increase of the used band. At that time, the first specifying unit  14   b  specifies the virtual machine based on the correspondence relation between the plurality of lines  28   a  and  28   b  and the virtual machines  21   a  to  21   d  which perform the back-up process using the lines  28   a  and  28   b . Herein, for example, when the back-up process is delayed, the back-up process is not completed within the regulated time. 
     An embodiment of the first specifying unit  14   b  will be described. For example, when the measurement of the loads of various resources and updating of the loads of various resources in the load information  13   c  described above are started by the acquisition unit  14   a , the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  determines whether or not there is an average load exceeding a predetermined value, for example, 90%, among the average loads of the CPU of the virtual machines  21   a  to  21   d  registered in the load information  13   c . The first specifying unit  14   b  determines whether or not there is an average load exceeding a predetermined value, for example, 90%, among the average loads of the memory of the virtual machines  21   a  to  21   d  registered in the load information  13   c . In addition, the first specifying unit  14   b  calculates the total of the average load of the line  28   a  due to the virtual machine  21   a  and the average load of the line  28   a  due to the virtual machine  21   c  registered in the load information  13   c , as an average load of the line  28   a . Further, the first specifying unit  14   b  calculates the total of the average load of the line  28   b  due to the virtual machine  21   b  and the average load of the line  28   b  due to the virtual machine  21   d  registered in the load information  13   c , as an average load of the line  28   b . Then, the first specifying unit  14   b  determines whether or not there is an average load exceeding a predetermined value, for example, 90%, among the average load of the line  28   a  and the average load of the line  28   b.    
     When it is determined that there is an average load exceeding a predetermined value (for example, 90%), the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  specifies the virtual machines having the average load exceeding the predetermined value among the virtual machines  21   a  to  21   d , and determines whether or not there is a percentage of completion equal to or smaller than a threshold value among the percentages of completion of the back-up process of the specified virtual machines. Herein, such a threshold value is a value calculated by the acquisition unit  14   a , and is a value obtained by multiplying 100 by a value obtained by dividing elapsed time from the start of the back-up process to the current time by expected time of the back-up process. For example, the back-up information  13   d  illustrated in the example of  FIG. 6  is stored in the memory unit  13 , and when the day is Monday and the current time is 2:00 am, the acquisition unit  14   a  calculates the threshold value as follows. That is, the acquisition unit  14   a  multiplies 100 by a value obtained by dividing 2 hours which is the elapsed time from the start of the back-up process to the current time by 5 hours which is the expected time of the back-up process, and calculates the threshold value as 40%. 
     When it is determined that there is a percentage of completion equal to or smaller than a threshold value among the percentages of completion of the back-up process of the specified virtual machines, the first specifying unit  14   b  determines whether or not there is negative progressing acceleration among progressing acceleration (%/s*s) of the back-up process with the percentage of completion which is equal to or smaller than the threshold value. Herein, the progressing acceleration is a value calculated by the acquisition unit  14   a . When it is determined by the first specifying unit  14   b  that there is a percentage of completion equal to or smaller than a threshold value among the percentages of completion of the back-up process of the specified virtual machines, the acquisition unit  14   a  calculates a rate of change of the percentage of completion for the last 5 minutes from the current time as progressing speed (%/s). The acquisition unit  14   a  calculates a rate of change of the progressing speed for the last 5 minutes from the current time as progressing acceleration (%/s*s). 
     When it is determined that there is negative progressing acceleration among the progressing acceleration in the back-up process with the percentage of completion equal to or smaller than the threshold value, the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  determines whether or not the average load exceeding the predetermined value (for example, 90%) is the average load of the line  28   a  or the average load of the line  28   b.    
     When it is determined that the average load exceeding the predetermined value (for example, 90%) is the average load of the line  28   a  or the average load of the line  28   b , the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  specifies the virtual machine corresponding to the line having the average load exceeding the predetermined value from the correspondence relation table  13   b . When there is one specified virtual machine, the first specifying unit  14   b  specifies the specified virtual machine as a movement target virtual machine. Meanwhile, when there is the plurality of specified virtual machines, the first specifying unit  14   b  specifies a virtual machine having the highest average load with respect to the line with the average load exceeding the predetermined value as the movement target virtual machine, from the plurality of specified virtual machines, with reference to the load information  13   c . For example, when the average load of the line  28   b  exceeds the predetermined value and the virtual machines  21   b  and  21   d  which corresponds to the line  28   b , the name of which is the route  2 , and executes the back-up programs B and D specified from the correspondence relation table  13   b , the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  specifies the virtual machine  21   d  having the higher average load with respect to the line  28   b  with the average load exceeding the predetermined value from the virtual machines  21   b  and  21   d  as the movement target virtual machine, with reference to the load information  13   c  illustrated in  FIG. 5 . Herein, the virtual machine  21   d  is specified from the virtual machines  21   b  and  21   d  because the average load, 95%, of the line  28   b  due to the virtual machine  21   d  is higher than the average load, 5%, of the line  28   b  due to the virtual machine  21   b  as illustrated in the load information  13   c  of  FIG. 5 . 
     Meanwhile, when it is determined that the average load exceeding the predetermined value (for example, 90%) is not the average load of the line  28   a  and the average load of the line  28   b , the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  specifies the virtual machine having the average load exceeding the predetermined value as the movement target virtual machine. 
     The second specifying unit  14   c  performs the following process based on the degree of completion of the back-up process. That is, when the specified movement target virtual machine is moved, the second specifying unit  14   c  specifies the management target server which satisfies the conditions in which the back-up process executed by the moved virtual machine is not delayed, from the plurality of management target servers  22  to  24 . 
     An embodiment of the second specifying unit  14   c  will be described. For example, when the movement target virtual machine is specified by the first specifying unit  14   b , the second specifying unit  14   c  calculates an average value of the usages of the CPU of the movement target virtual machine from the start of the back-up process to the current time measured by the acquisition unit  14   a . The second specifying unit  14   c  calculates a first value obtained by dividing the calculated average value by the data quantity of the data in the system area of the movement target virtual machine which has been transmitted to the storage  27 . The second specifying unit  14   c  calculates a second value obtained by multiplying the data quantity of the data in the system area of the movement target virtual machine which is not transmitted to the storage  27  by the calculated first value, as a value with the following content. That is, the second specifying unit  14   c  calculates the second value, as the usage (GHz) of the CPU of the management target server at the movement destination desired for completing the back-up process of the movement target virtual machine within the regulated time. 
     When the movement target virtual machine is specified by the first specifying unit  14   b , the second specifying unit  14   c  calculates an average value of the usages of the memory of the movement target virtual machine from the start of the back-up process to the current time measured by the acquisition unit  14   a . The second specifying unit  14   c  calculates a third value obtained by dividing the calculated average value by the data quantity of the data in the system area of the movement target virtual machine which has been transmitted to the storage  27 . The second specifying unit  14   c  calculates a fourth value obtained by multiplying the data quantity of the data in the system area of the movement target virtual machine which is not transmitted to the storage  27  by the calculated third value, as a value with the following content. That is, the second specifying unit  14   c  calculates the fourth value, as the usage (GB) of the memory of the management target server at the movement destination desired for completing the back-up process of the movement target virtual machine within the regulated time. 
     When the movement target virtual machine is specified by the first specifying unit  14   b , the second specifying unit  14   c  performs the following process. That is, the second specifying unit  14   c  calculates an average value of the data quantities (Gbps) of the data of the back-up target flowing, for 1 second, to the line used when the movement target virtual machine executes the back-up process from the start of the back-up process to the current time. The data quantities of the data of the back-up target flowing, for 1 second, to the line used when the movement target virtual machine executes the back-up process from the start of the back-up process to the current time, are measured by the acquisition unit  14   a . The second specifying unit  14   c  calculates a fifth value obtained by dividing the calculated average value by the data quantity of the data in the system area of the movement target virtual machine which has been transmitted to the storage  27 . The second specifying unit  14   c  calculates a sixth value obtained by multiplying the data quantity of the data in the system area of the movement target virtual machine which is not transmitted to the storage  27  by the calculated fifth value, as a value with the following content. That is, the second specifying unit  14   c  calculates the sixth value, as the band (Gbps) of the line connected to the management target server at the movement destination desired for completing the back-up process of the movement target virtual machine within the regulated time. 
     The second specifying unit  14   c  searches the management target server which satisfies three conditions described below from the management target servers  22  to  24 . The first condition is a condition of including the CPU in which a usage equal to or greater than the calculated usage (GHz) of the CPU of the management target server at the movement destination may be used. The second condition is a condition of including the memory in which a usage equal to or greater than the calculated usage (GB) of the memory of the management target server at the movement destination may be used. The third condition is a condition of being connected to the line in which a band equal to or greater than the calculated band (Gbps) of the line may be used. When there is one management target server satisfying the three conditions as a result of the searching, the second specifying unit  14   c  specifies the obtained management target server as a management target server for moving the movement target virtual machine. 
     When there are the plurality of management target servers satisfying the three conditions as a result of the searching, the second specifying unit  14   c  performs the following process. That is, the second specifying unit  14   c  specifies the management target server having the smallest available usage of the CPU and the available usage of the memory from the plurality of obtained management target servers, as the management target server for moving the movement target virtual machine. Herein, an example of a factor of specifying the management target server having the smallest available usage of the CPU and the available usage of the memory as the management target server for moving the movement target virtual machine will be described. The requirement for the back-up process is to complete the process within the regulated time and not to rapidly complete the process. Accordingly, the second specifying unit  14   c  specifies the management target server having a small usable resource quantity, such as the management target server having the smallest available usage of the CPU and available usage of the memory, from the management target servers which complete the back-up process within the regulated time. Therefore, it is possible to suppress a decrease in the performance of the process of the virtual machine executed on the management target server, due to the movement of the virtual machine which executes the back-up process. 
     Meanwhile, when there is no management target server satisfying the three conditions as a result of the searching, the second specifying unit  14   c  performs the following process. That is, the second specifying unit  14   c  moves the virtual machines  22   a ,  22   b ,  23   a , and  24   a  operated on the management target servers  22  to  24  to the specified management target server, and controls so that the available resource of any management target server from the management target servers  22  to  24  becomes greater. The second specifying unit  14   c  performs a process of searching the management target server satisfying the three conditions. When there is one management target server satisfying the three conditions as a result of the searching, the second specifying unit  14   c  specifies the obtained management target server as the management target server for moving the movement target virtual machine. In addition, when there is the plurality of management target servers satisfying the three conditions as a result of the searching, the second specifying unit  14   c  performs the following process. That is, the second specifying unit  14   c  specifies the management target server having the smallest available usage of the CPU and the available usage of the memory from the plurality of obtained management target servers, as the management target server for moving the movement target virtual machine. 
     When an increase of at least one used band of lines  28   a  and  28   b  is detected and delay of the back-up process using the line with the detected increase of the used band is detected based on the degree of completion of the back-up process, the movement control unit  14   d  performs the following process. That is, the movement control unit  14   d  moves any one of the virtual machines for performing the back-up process by using the line with the detected increase of the used band, to any management target server of the plurality of management target servers  22  to  24  from the back-up server  21 . 
     An embodiment of the movement control unit  14   d  will be described. For example, the movement control unit  14   d  transmits a migration instruction of moving the movement target virtual machine specified by the first specifying unit  14   b  to the management target server specified by the second specifying unit  14   c , to the VM host  21   e . Accordingly, the movement target virtual machine is moved to the management target server for moving the movement target virtual machine. For example, when the virtual machine  21   d  is specified as the movement target virtual machine by the first specifying unit  14   b  and the management target server  23  is specified as the management target server for moving the movement target virtual machine by the second specifying unit  14   c , the movement control unit  14   d  performs the following process. That is, the movement control unit  14   d  transmits the migration instruction of moving the virtual machine  21   d  to the management target server  23 , to the VM host  21   e . Accordingly, as illustrated in  FIG. 8 , the virtual machine  21   d  is moved to the management target server  23 . The movement control unit  14   d  updates the correspondence relation table  13   b  so that the name of the line connected to the management target server to which the movement target virtual machine is moved is associated and registered with respect to the identifier of the back-up program executed by the movement target virtual machine. 
     The control unit  14  is a circuit such as the CPU. 
     Flow of Process 
     Next, a flow of the process executed by the management server  10  according to the example will be described.  FIGS. 9A and 9B  are flowcharts illustrating a procedure of a controlling process according to an example. The controlling process according to an example is executed when the acquisition unit  14   a , for example, determines that the current time is in the time zone for performing the back-up process registered in the back-up information  13   d , with reference to the back-up information  13   d.    
     As illustrated in  FIG. 9A , the acquisition unit  14   a  acquires the maximum allowable quantities of the loads of various resources (CPU, memory, and lines connected to each server) of each server of the back-up server  21  and the management target servers  22  to  24  from the allowable load quantity table  13   a  (S 101 ). 
     Next, the acquisition unit  14   a  executes the correspondence relation table generation process (S 102 ). The correspondence relation table generation process will be described.  FIG. 10  is a flowchart illustrating a procedure of the correspondence relation table generation process according to the example. As illustrated in  FIG. 10 , the acquisition unit  14   a  calculates the total of maximum bands of the lines  28   a  and  28   b  connected to the back-up server  21  (S 201 ). 
     The acquisition unit  14   a  calculates each rate of the bands of the lines  28   a  and  28   b  with respect to the calculated total of the bands (S 202 ). The acquisition unit  14   a  specifies the virtual machine for executing the back-up process (S 203 ). 
     The acquisition unit  14   a  determines whether or not there is an unselected virtual machine among the specified virtual machines (S 204 ). When it is determined that there is the unselected virtual machine (S 204 ; Yes), the acquisition unit  14   a  selects one unselected virtual machine (S 205 ). 
     The acquisition unit  14   a  associates the selected virtual machine with the lines  28   a  and  28   b  according to the calculated rate (S 206 ), and the process returns to S 204 . 
     Meanwhile, when it is determined that there is no unselected virtual machine (S 204 ; No), the acquisition unit  14   a  registers the association of the associated virtual machine and the line in the correspondence relation table  13   b  (S 207 ), and stores and returns the process results in the internal memory of the control unit  14 . 
     By returning to the description of  FIG. 9A , the acquisition unit  14   a  controls the virtual machine  21   a  to  21   d  to start the back-up process (S 103 ). The acquisition unit  14   a  starts the measurement of the loads of various resources when the virtual machines  21   a  to  21   d  execute the back-up programs A to D, and starts the updating of the loads of various resources in the load information  13   c  (S 104 ). 
     The first specifying unit  14   b  determines whether or not there is the average load exceeding a predetermined value (for example, 90%), among the average loads of the CPU of the virtual machines  21   a  to  21   d  registered in the load information  13   c . The first specifying unit  14   b  determines whether or not there is an average load exceeding a predetermined value, for example, 90%, among the average loads of the memory of the virtual machines  21   a  to  21   d  registered in the load information  13   c . In addition, the first specifying unit  14   b  calculates the total of the average load of the line  28   a  due to the virtual machine  21   a  and the average load of the line  28   a  due to the virtual machine  21   c  registered in the load information  13   c , as an average load of the line  28   a . Further, the first specifying unit  14   b  calculates the total of the average load of the line  28   b  due to the virtual machine  21   b  and the average load of the line  28   b  due to the virtual machine  21   d  registered in the load information  13   c , as an average load of the line  28   b . Then, the first specifying unit  14   b  determines whether or not there is an average load exceeding a predetermined value, for example, 90%, among the average load of the line  28   a  and the average load of the line  28   b  (S 105 ). When it is determined that there is no average load exceeding a predetermined value (for example, 90%) (S 105 ; No), the first specifying unit  14   b  causes the process to proceed to S 121  which will be described later. 
     Meanwhile, when it is determined that there is an average load exceeding a predetermined value (for example, 90%) (S 105 ; Yes), the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  specifies the virtual machines having the average load exceeding the predetermined value among the virtual machines  21   a  to  21   d , and determines whether or not there is a percentage of completion equal to or smaller than a threshold value among the percentages of completion of the back-up process of the specified virtual machines (S 106 ). When there is no percentage of completion equal to or smaller than a threshold value among the percentages of completion of the back-up process of the specified virtual machines (S 106 ; No), the first specifying unit  14   b  causes the process to proceed to S 121  which will be described later. 
     Meanwhile, when there is a percentage of completion equal to or smaller than a threshold value among the percentages of completion of the back-up process of the specified virtual machines (S 106 ; Yes), the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  determines whether or not there is negative progressing acceleration among progressing acceleration (%/s*s) of the back-up process with the percentage of completion which is equal to or smaller than the threshold value (S 107 ). When it is determined that there is no negative progressing acceleration (S 107 ; No), the first specifying unit  14   b  causes the process to proceed to S 121  which will be described later. 
     Meanwhile, when it is determined that there is negative progressing acceleration (S 107 ; Yes), the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  determines whether or not the average load exceeding the predetermined value (for example, 90%) is the average load of the line  28   a  or the average load of the line  28   b  (S 108 ). 
     When it is determined that the average load exceeding the predetermined value (for example, 90%) is the average load of the line  28   a  or the average load of the line  28   b  (S 108 ; Yes), the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  specifies the virtual machine corresponding to the line having the average load exceeding the predetermined value from the correspondence relation table  13   b  (S 109 ). 
     When there is one specified virtual machine, the first specifying unit  14   b  specifies the specified virtual machine as a movement target virtual machine. When there is the plurality of specified virtual machines, the first specifying unit  14   b  specifies a virtual machine having the highest average load with respect to the line with the average load exceeding the predetermined value as the movement target virtual machine, from the plurality of specified virtual machines, with reference to the load information  13   c  ( 5110 ). 
     Meanwhile, when it is determined that the average load exceeding the predetermined value (for example, 90%) is not the average load of the line  28   a  and the average load of the line  28   b  (S 108 ; No), the first specifying unit  14   b  performs the following process. That is, the first specifying unit  14   b  specifies the virtual machine having the average load exceeding the predetermined value as the movement target virtual machine (S 111 ). 
     The second specifying unit  14   c  calculates the usage (GHz) of the CPU of the management target server at the movement destination desired for completing the back-up process of the movement target virtual machine within the regulated time. The second specifying unit  14   c  calculates the usage (GB) of the memory of the management target server at the movement destination desired for completing the back-up process of the movement target virtual machine within the regulated time. The second specifying unit  14   c  calculates the band (Gbps) of the line connected to the management target server at the movement destination desired for completing the back-up process of the movement target virtual machine within the regulated time (S 112 ). 
     The second specifying unit  14   c  searches the management target server which satisfies the three conditions described above from the management target servers  22  to  24  (S 113 ). The second specifying unit  14   c  determines whether or not there is the management target server satisfying the three conditions as a result of the searching (S 114 ). When it is determined that there is a management target server satisfying the three conditions (S 114 ; Yes), the second specifying unit  14   c  determines whether or not there are the plurality of obtained management target servers (S 115 ). When there is one management target server (S 115 ; No), the second specifying unit  14   c  specifies the obtained management target server as the management target server for moving the movement target virtual machine (S 116 ) and causes the process to proceed to S 119  which will be described later. 
     Meanwhile, when it is determined that there are the plurality of obtained management target servers (S 115 ; Yes), the second specifying unit  14   c  performs the following process. That is, the second specifying unit  14   c  specifies the management target server having the smallest available usage of the CPU and the available usage of the memory from the plurality of obtained management target servers, as the management target server for moving the movement target virtual machine (S 117 ) and causes the process to proceed to S 119  which will be described later. 
     When it is determined that there is no management target server satisfying the three conditions as a result of the searching (S 114 ; No), the second specifying unit  14   c  performs the following process. That is, the second specifying unit  14   c  moves the virtual machines  22   a ,  22   b ,  23   a , and  24   a  to the specified management target server, and controls so that the available resource of any management target server from the management target servers  22  to  24  becomes greater (S 118 ), and the process returns to S 113 . 
     The movement control unit  14   d  transmits a migration instruction of moving the movement target virtual machine specified by the first specifying unit  14   b  to the management target server specified by the second specifying unit  14   c , to the VM host  21   e  (S 119 ). The movement control unit  14   d  performs the following process, so that the name of the line connected to the management target server to which the movement target virtual machine is moved is associated and registered with respect to the identifier of the back-up program executed by the movement target virtual machine. That is, the movement control unit  14   d  updates the correspondence relation table  13   b  (S 120 ). 
     The movement control unit  14   d  determines whether or not the back-up process is in progress (S 121 ). When it is determined that the back-up process is in progress (S 121 ; Yes), the movement control unit  14   d  causes the process to return to S 105 . Meanwhile, when it is determined that the back-up process is not in progress (S 121 ; No), the movement control unit  14   d  causes the controlling process to end. 
     As described above, the management server  10  according to the example acquires the band loads of the lines  28   a  and  28   b , the resource usages of the plurality of management target servers  22  to  24 , the degree of completion of the back-up process executed by the virtual machines  21   a  to  21   d . When an increase of at least one used band of lines  28   a  and  28   b  is detected and delay of the back-up process using the line with the detected increase of the used band is detected based on the degree of completion, the management server  10  performs the following process. That is, the management server  10  moves any one of the virtual machines  21   a  to  21   d  for performing the back-up process by using the line with the detected increase of the used band, to any of the plurality of management target servers  22  to  24  from the back-up server  21 . The management target server at the movement destination of the movement target virtual machine is determined with the condition that no delay of the back-up process executed by the virtual machine to be moved, when the movement target virtual machine is moved, is expected based on the degree of completion. Therefore, according to the management server  10 , when the route is a factor of the delay of the back-up process, it is possible to suppress the delay of the back-up process. 
     The management server  10  specifies the management target server having the smallest available resource among the management target servers satisfying the conditions described above, as the management target server at the movement destination of the movement target virtual machine. Accordingly, it is possible to suppress a decrease in the performance of the process of the virtual machine executed on the management target server, due to the movement of the virtual machine which executes the back-up process. 
     When it is determined that the back-up process tends to be delayed, based on the progressing acceleration based on the percentages of completion indicating a degree of completion of the back-up process using the line with the detected increase of the used band, the management server  10  performs the following process. That is, the management server  10  specifies the virtual machine in which the back-up process tends to be delayed based on the degree of completion of the back-up process, as the movement target virtual machine, among the virtual machines  21   a  to  21   d , based on the registered content of the correspondence relation table  13   b . Accordingly, the management server  10  may specify the movement target virtual machine by detecting the progressing acceleration which is an index for detecting the delay tendency based on the degree of completion of the back-up process, and therefore the management server  10  may specify the movement target virtual machine by detecting the delay tendency. 
     Hereinabove, the examples regarding the system and the apparatus of the embodiment have been described, but the embodiment may be realized with various other examples, other than the examples described above. 
     For example, the back-up server  21  and the plurality of management target servers  22  to  24  may be connected to the plurality of redundant lines, and the virtual machines operating on the management target servers may transmit the data in system area to the back-up server  21 . In this case, the virtual machine for performing the back-up process operating on the back-up server  21  may perform the back-up process with the same method as described above, by using the data in the system area transmitted from the virtual machines operating on the management target servers. 
     Among the processes described in the examples, all or a part of the processes described to be automatically performed may be manually performed. Among the processes described in the examples, all or a part of the processes described to be manually performed may be automatically performed with the well-known method. 
     The processes in the steps of the processes described in the examples may be arbitrarily divided into several processes or may be combined with each other, according to various loads or state of use. In addition, the steps may be omitted. 
     The order of the processes in the steps of the processes described in the examples may be changed according to various loads or state of use. 
     The constituent elements of the devices illustrated in the drawings are conceptual in functions, and the configurations illustrated in the drawings are not physically desired. That is, the detailed state of the dispersion and integration of the devices is not limited to the drawings, and all or a part of the devices may be configured to be functionally or physically dispersed and integrated in an arbitrary unit, according to various loads or state of use. 
     Controlling Process 
     Various processes of the management server  10  described in the examples described above may be realized by executing the program prepared in advance by a computer system such as a personal computer or a work station. Hereinafter, an example of a computer which executes the controlling program, including the same function as that of the management server  10  described in the examples described above will be described, with reference to  FIG. 11 .  FIG. 11  is a diagram illustrating a computer which executes the controlling program. 
     As illustrated in  FIG. 11 , a computer  300  includes a CPU  310 , a ROM  320 , an HDD  330 , a RAM  340 , a display device  350 , and a communication device  360 . The devices  310  to  360  are connected to each other through a bus  370 . 
     The display device  350  is, for example, a liquid crystal display. The display device  350  corresponds to the display unit  11 . The communication device  360  is a network card or the like. The communication device  360  corresponds to the communication unit  12 . 
     A basic program such as an operating system (OS) is stored in the ROM  320 . A controlling program  330   a  which exhibits the same function as that of the acquisition unit  14   a , the first specifying unit  14   b , the second specifying unit  14   c , and the movement control unit  14   d  illustrated in the examples described above is stored in advance in the HDD  330 . The HDD  330  includes various data items stored in the memory unit  13 . 
     The CPU  310  reads out the controlling program  330   a  from the HDD  330  and executes the controlling program. 
     The CPU  310  reads out the various data items from the HDD  330  and stores the data items in the RAM  340 . The CPU  310  further executes the controlling program  330   a  by using the various data items stored in the RAM  340 . Regarding the data items stored in the RAM  340 , all of the data items may not be stored in the RAM  340 . The data items to be used in the process may be stored in the RAM  340 . 
     The controlling program  330   a  described above may not be stored in the HDD  330  from the initial stage. 
     For example, the program may be stored in a “portable physical medium” such as a flexible disk (FD), a CD-ROM, a DVD, a magnet-optical disk, or an IC card to be inserted into the computer  300 . Then, the computer  300  may read out the program and execute the program from the medium described above. 
     In addition, the program may be stored in “another computer (or server)” connected to the computer  300  through a public line, the Internet, a LAN, or a WAN. Then, the computer  300  may read out the program and execute the program from the computer or the server. 
     All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.