Abstract:
A storage system comprises storage devices providing logical volumes. The storage devices are divided into a plurality of types of tiers having different performance levels. A controller is operable to control to store data to a logical volume of the logical volumes. The controller is configured to receive a command commanding to copy data to deploy a template to a logical volume of the logical volumes or to back up data to a logical volume of the logical volumes. In response to the command, the controller is configured to allocate a storage area of a tier of the plurality of types of tiers to the logical volume. The tier of the storage area to allocate to the logical volume is determined based on whether the command received by the controller is to copy data to the template to the logical volume or to back up data to the logical volume.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to tier management and, more particularly, to a method and an apparatus of tier management to deploy and backup volumes. 
         [0002]    In recent years, thin provisioning has become popular. Thin provisioning is a method for allocating area for a storage system that receives a write command to an unallocated area and allocates physical devices in response to the write commands. Storage systems may also reallocate frequently accessed allocated area to fast and expensive media and rarely accessed allocated area to slow and cheap media. Generally, when storage systems receive a write command to an unallocated area, the storage systems allocates default tier area to the unallocated area. 
         [0003]    According to one storage management method, a management server sends a volume copy command and a storage subsystem copies a volume to deploy or backup a volume (see  FIG. 2 ). There is no negative effect to an application server because not the application server but the storage subsystem copies the volume. Copied data for deploy or backup is located on the default tier. Generally, the default tier is tier  1  or tier  2 . If the copied data is for backup, there is no access to the copied data and the copied data is moved to tier  3 . There are two problems. The first problem arises when active data cannot be located on tier  1  and tier  2  because a lot of copied data for backup is located on tier  1  or tier  2 . The active data should be located on tier  1  or tier  2  and the backup data should be located on tier  3 . The second problem arises when the backup data is moved to tier  3  because it creates a negative effect to the storage subsystem which moves the backup data to tier  3 . 
         [0004]    According to US2011/0202705, an administrator can locate a specified volume to a specified tier. However, the storage subsystem does not know whether a volume copy command from the management server is for deploy or backup. Therefore, the storage subsystem cannot locate the volume to an applicable or appropriate tier. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    Exemplary embodiments of the invention provide a system in which a storage subsystem determines volume tier policy based on the purpose of a volume copy command. If the purpose is to deploy, the storage subsystem allocates an applicable tier based on the number of access to pages of the volume. If the purpose is to backup, the storage subsystem allocates tier  3  to pages of the volume (see  FIG. 1 ). In this way, active data can be located on tier  1  and tier  2  and there is no negative effect to the storage. 
         [0006]    In one embodiment, a management server appends the purpose of copy to the volume copy command. In another embodiment, the storage subsystem determines the purpose of copy based on information about template volumes. The storage subsystem acquires the information about the template volumes from the management server or an administrator inputs the information about the template volumes. 
         [0007]    In accordance with an aspect of the present invention, a storage system comprises: a plurality of storage devices providing a plurality of logical volumes, the plurality of storage devices being divided into a plurality of types of tiers having different performance levels; and a controller operable to control to store data to a logical volume of the plurality of logical volumes provided by the storage devices. The controller is configured to receive a command commanding to copy data to deploy a template to a logical volume of the plurality of logical volumes or to back up data to a logical volume of the plurality of logical volumes. In response to the command received by the controller, the controller is configured to allocate a storage area of a tier of the plurality of types of tiers to the logical volume. The tier of the storage area to allocate to the logical volume is determined based on whether the command received by the controller is to copy data to the template to the logical volume or to back up data to the logical volume. 
         [0008]    In some embodiments, the tier of the storage area to allocate to the logical volume for copying data to deploy the template to the logical volume is a higher performance tier than the tier of the storage area to allocate to the logical volume for backing up data to the logical volume. The tier of the storage area to allocate to the logical volume for backing up data to the logical volume is a lowest tier of all the tiers. The tier of the storage area to allocate to the logical volume for copying data to deploy the template to the logical volume is determined based on a number of access to pages of the logical volume, the tier for a larger number of access being a same performance tier as or a higher performance tier than the tier for a lower number of access. The command includes information specifying whether the command is to copy data to the template to the logical volume or to back up data to the logical volume. 
         [0009]    In specific embodiments, the command includes information on a source storage volume from which to copy data to the logical volume and includes no information specifying whether the command is to copy data to the template to the logical volume or to back up data to the logical volume. The controller is configured to obtain template information specifying a storage device and a storage volume in the storage device for storing the template. If the source storage volume is same as the storage volume for storing the template, then the command is to copy data to the template. The template information is obtained from a management computer or from a template volume input by an administrator. The template is a virtual machine template. 
         [0010]    Another aspect of the invention is directed to a method of storing data to a logical volume of a plurality of logical volumes provided by a plurality of storage devices which are divided into a plurality of types of tiers having different performance levels in a storage system, in response to a command received by a controller of the storage system, commanding to copy data to a template to a logical volume of the plurality of logical volumes or to back up data to a logical volume of the plurality of logical volumes. The method comprises: determining, by the controller, a tier of a storage area to allocate to the logical volume based on whether the command is to copy data to the template to the logical volume or to back up data to the logical volume; and allocating to the logical volume, by the controller, the storage area of the determined tier of the plurality of types of tiers. 
         [0011]    Another aspect of this invention is directed to a computer-readable storage medium storing a plurality of instructions for controlling a data processor to store data to a logical volume of a plurality of logical volumes provided by a plurality of storage devices which are divided into a plurality of types of tiers having different performance levels in a storage system, in response to a command received by a controller of the storage system, commanding to copy data to a template to a logical volume of the plurality of logical volumes or to back up data to a logical volume of the plurality of logical volumes. The plurality of instructions comprise: instructions that cause the data processor to determine a tier of a storage area to allocate to the logical volume based on whether the command is to copy data to the template to the logical volume or to back up data to the logical volume; and instructions that cause the data processor to allocate to the logical volume the storage area of the determined tier of the plurality of types of tiers. 
         [0012]    These and other features and advantages of the present invention will become apparent to those of ordinary skill in the art in view of the following detailed description of the specific embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a hardware configuration of a system showing the allocation of tier  3  storage to backup data and the allocation of tier  1  and tire  2  to active data. 
           [0014]      FIG. 2  is a hardware configuration of a system showing the allocation of tier  1  or tier  2  as the default tier  3  to copied data including active data and backup data, and the need to move backup data to tier  3  by the storage subsystem. 
           [0015]      FIG. 3  illustrates an example of a hardware configuration of an information system in which the method and apparatus of the invention may be applied. 
           [0016]      FIG. 4  illustrates an example of the memory in the application server of  FIG. 3 . 
           [0017]      FIG. 5  illustrates an example of the memory in the storage subsystem of  FIG. 3  according to the first embodiment of the invention. 
           [0018]      FIG. 6  illustrates an example of the memory in the management server of  FIG. 3 . 
           [0019]      FIG. 7  shows an example of the VHD location information. 
           [0020]      FIG. 8  shows an example of the server information. 
           [0021]      FIG. 9  shows an example of the VM information. 
           [0022]      FIG. 10  shows an example of the RAID group information. 
           [0023]      FIG. 11  shows an example of the logical volume information. 
           [0024]      FIG. 12  shows an example of the storage pool information. 
           [0025]      FIG. 13  shows an example of the virtual volume information. 
           [0026]      FIG. 14  shows an example of the virtual volume tier policy information. 
           [0027]      FIG. 15  shows an example of the tier definition information. 
           [0028]      FIG. 16  shows an example of the VM template information. 
           [0029]      FIG. 17  shows an example of the VM backup information. 
           [0030]      FIG. 18  shows an example of the VM deploy screen. 
           [0031]      FIG. 19  shows an example of the VM restore screen. 
           [0032]      FIG. 20  shows an example of a VHD read command. 
           [0033]      FIG. 21  shows an example of a VHD write command. 
           [0034]      FIG. 22  shows an example of a read command. 
           [0035]      FIG. 23  shows an example of a write command. 
           [0036]      FIG. 24  shows an example of a VM deploy command. 
           [0037]      FIG. 25  shows an example of a volume copy command according to the first embodiment. 
           [0038]      FIG. 26  shows an example of a volume copy command reply. 
           [0039]      FIG. 27  shows an example of a volume delete command. 
           [0040]      FIG. 28  is an example of a flow diagram showing a process performed by the VHD control program. 
           [0041]      FIG. 29  is an example of a flow diagram showing a process performed by the disk control program. 
           [0042]      FIG. 30  is an example of a flow diagram showing the process by which the page move program moves pages. 
           [0043]      FIG. 31  is an example of a flow diagram showing the process by which the VM deploy program deploys a VM. 
           [0044]      FIG. 32  is an example of a flow diagram showing the process by which the VM backup program backs up a VM regularly every backup cycle. 
           [0045]      FIG. 33  is an example of a flow diagram showing the process to be performed when the volume configuration program receives the volume copy command or the volume delete command according to the first embodiment. 
           [0046]      FIG. 34  illustrates an example of the memory in the storage subsystem of  FIG. 3  according to the second embodiment. 
           [0047]      FIG. 35  shows an example of the template volume input screen according to the second embodiment. 
           [0048]      FIG. 36  shows an example of a volume copy command according to the second embodiment. 
           [0049]      FIG. 37  is an example of a flow diagram showing the process to be performed when the volume configuration program receives the volume copy command or the volume delete command according to the second embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0050]    In the following detailed description of the invention, reference is made to the accompanying drawings which form a part of the disclosure, and in which are shown by way of illustration, and not of limitation, exemplary embodiments by which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. Further, it should be noted that while the detailed description provides various exemplary embodiments, as described below and as illustrated in the drawings, the present invention is not limited to the embodiments described and illustrated herein, but can extend to other embodiments, as would be known or as would become known to those skilled in the art. Reference in the specification to “one embodiment,” “this embodiment,” or “these embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention, and the appearances of these phrases in various places in the specification are not necessarily all referring to the same embodiment. Additionally, in the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to one of ordinary skill in the art that these specific details may not all be needed to practice the present invention. In other circumstances, well-known structures, materials, circuits, processes and interfaces have not been described in detail, and/or may be illustrated in block diagram form, so as to not unnecessarily obscure the present invention. 
         [0051]    Furthermore, some portions of the detailed description that follow are presented in terms of algorithms and symbolic representations of operations within a computer. These algorithmic descriptions and symbolic representations are the means used by those skilled in the data processing arts to most effectively convey the essence of their innovations to others skilled in the art. An algorithm is a series of defined steps leading to a desired end state or result. In the present invention, the steps carried out require physical manipulations of tangible quantities for achieving a tangible result. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals or instructions capable of being stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, instructions, or the like. It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, as apparent from the following discussion, it is appreciated that throughout the description, discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” “displaying,” or the like, can include the actions and processes of a computer system or other information processing device that manipulates and transforms data represented as physical (electronic) quantities within the computer system&#39;s registers and memories into other data similarly represented as physical quantities within the computer system&#39;s memories or registers or other information storage, transmission or display devices. 
         [0052]    The present invention also relates to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may include one or more general-purpose computers selectively activated or reconfigured by one or more computer programs. Such computer programs may be stored in a computer-readable storage medium, such as, but not limited to optical disks, magnetic disks, read-only memories, random access memories, solid state devices and drives, or any other types of media suitable for storing electronic information. The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may be used with programs and modules in accordance with the teachings herein, or it may prove convenient to construct a more specialized apparatus to perform desired method steps. In addition, the present invention is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the invention as described herein. The instructions of the programming language(s) may be executed by one or more processing devices, e.g., central processing units (CPUs), processors, or controllers. 
         [0053]    Exemplary embodiments of the invention, as will be described in greater detail below, provide apparatuses, methods and computer programs for tier management to deploy and backup volumes. 
       First Embodiment 
       [0054]    A. System Configuration 
         [0055]      FIG. 3  illustrates an example of a hardware configuration of an information system in which the method and apparatus of the invention may be applied. The system comprises one or more application servers  300 , a SAN (Storage Area Network)  320 , a LAN (Local Area Network)  340 , one or more storage subsystems  360 , and a management server  380 . The application server  300  comprises a CPU (Central Processing Unit)  301 , a memory  302 , a HDD (Hard Disk Drive)  303 , a SAN interface  304 , and a LAN interface  305 . The CPU  301  reads programs from the memory  302  and executes the programs. The memory  302  reads programs and data from the HDD  303  when the application server  300  starts, and it stores the programs and the data. The HDD  303  stores programs and data. The SAN interface  304  connects the application server  300  and the SAN  320 . The LAN interface  305  connects the application server  300  and the LAN  340 . The SAN  320  connects the application server  300  and the storage subsystem  360 . The application server  300  uses the SAN  320  to send application data to the storage subsystem  360  and receive application data from the storage subsystem  360 . The application server  300 , the storage subsystem  360 , and the management server  380  use the LAN  340  to send management data and receive management data. The LAN  340  connects the application server  300 , the storage subsystem  360 , and the management server  380 . 
         [0056]    The storage subsystem  360  comprises a SAN interface  361 , a LAN interface  362 , a CPU  363 , a memory  364 , a disk interface  365 , a HDD  366 , and a SSD (Solid State Drive)  367 . The SAN interface  361  connects the storage subsystem  360  and the SAN  320 . The LAN interface  362  connects the storage subsystem  360  and the LAN  340 . The CPU  363  reads programs from the memory  364  and executes the programs. The memory  364  reads programs and data from the HDD  366  and the SSD  367  when the storage subsystem  360  starts and stores the programs and the data. The disk interface  365  connects the storage subsystem  360 , the HDD  366 , and the SSD  367 . The HDD  366  stores programs and data. The SSD  367  stores programs and data. The management server  380  comprises a CPU  381 , a memory  382 , a HDD  383 , and a LAN interface  384 . The CPU  381  reads programs from the memory  382  and executes the programs. The memory  382  reads programs and data from the HDD  383  when the management server  380  starts, and it stores the programs and the data. The HDD  383  stores programs and data. The LAN interface  384  connects the management server  380  and the LAN  340 . 
         [0057]      FIG. 4  illustrates an example of the memory  302  in the application server  300  of  FIG. 3 . The memory  302  comprises a hypervisor  401 , VHD (Virtual Hard Disk) control program  402 , VHD location information  403 , server information  404 , VM (Virtual Machine) information  405 , a VM  406 , an OS (Operating System) program  407 , and an application program  408 . The hypervisor runs the OS program  407  in the VM  406 . The OS program  407  executes the application program  408 . The application program  408  (e.g., database program) sends a VHD read command and a VHD write command to the VHD control program  402  to read data from the storage subsystem  360 , process data, and write the results to the storage subsystem  360 . VHD is a file format that provides a virtual hard disk drive to VM. The VHD control program  402  manages VHDs with the VHD location information  403 . When the VHD control program  402  receives the VHD read command from the application program  408 , the VHD control program  402  reads data from the storage subsystem  360  and sends the result to the application program  408 . When the VHD control program  402  receives the VHD write command from the application program  408 , the VHD control program  402  writes the data to the storage subsystem  360  and sends the result to the application program  408 . 
         [0058]      FIG. 5  illustrates an example of the memory  364  in the storage subsystem  360  of  FIG. 3  according to the first embodiment of the invention. The memory  364  comprises a disk control program  501 , RAID (Redundant Arrays of Inexpensive (or Independent) Disks) group information  502 , logical volume information  503 , storage pool information  504 , virtual volume information  505 , virtual volume tier policy information  506 , tier definition information  507 , a page move program  508 , and a volume configuration program  509 . The disk control program  501  receives a read command and a write command from the application server  300 , reads data from the HDD  366  and the SSD  367 , and writes data to the HDD  366  and the SSD  367  using the RAID group information  502 , the logical volume information  503 , the storage pool information  504 , the virtual volume information  505 , virtual volume tier policy information  506 , and the tier definition information  507 . 
         [0059]      FIG. 6  illustrates an example of the memory  382  in the management server  380  of  FIG. 3 . The memory  382  comprises an information acquisition program  601 , a VM deploy program  602 , a VM backup program  603 , a VM restore program  604 , VM template information  605 , VM backup information  606 , a VM deploy screen  607 , and a VM restore screen  608 . 
         [0060]      FIG. 7  shows an example of the VHD location information  403 . The VHD location information  403  includes columns of a VHD name  701 , a VHD address  702 , a volume name  703 , and a volume address  704 . The VHD location information  403  shows data in an area specified by the VHD name  701  and the VHD address  702  is stored in an area specified by the volume name  703  and the volume address  704 .  FIG. 7  shows two sample entries  705 ,  706 . 
         [0061]      FIG. 8  shows an example of the server information  404 . The server information  404  includes columns of a server name  801 , a number of CPU  802 , a used number of CPU  803 , a memory capacity  804 , and a used memory  805 . The server information  404  shows the specification of the application server  300 . The server name  801  shows the name of the application server  300 . The number of CPU  802  shows the number of CPU that the application server  300  has. The used number of CPU  803  shows the number of CPU that is allocated to the VM  406 . The memory capacity  804  shows the capacity that the application server  300  has. The used memory  805  shows the amount of memory that is allocated to the VM  406 . 
         [0062]      FIG. 9  shows an example of the VM information  405 . The VM information  405  includes columns of a server name  901 , a VM name  902 , a number of CPU  903 , a memory  904 , a volume name  905 , a storage capacity  906 , a backup cycle  907 , and a number of generation  908 . The server name  901  shows that the VM  406  is running on. The VM name  902  shows the name of the VM  406 . The number of CPU  903  shows the number of CPU that is allocated to the VM  406 . The memory  904  shows the amount of memory that is allocated to the VM  406 . The volume name  905  shows the volume name that is allocated to the VM  406 . The storage capacity  906  shows the amount of storage that is allocated to the VM  406 . The storage subsystem  360  copies a volume specified by the volume name  905  every cycle specified by the backup cycle  907  and retains the copied volumes of the number specified by the number of generation  908 .  FIG. 9  shows two sample entries  909 ,  910 . 
         [0063]      FIG. 10  shows an example of the RAID group information  502 . The RAID group information  502  includes columns of a RAID group name  1001 , a media name  1002 , a RAID level  1003 , a media type  1004 , and a capacity  1005 . The RAID group name  1001  shows the name of the RAID groups. The media name  1002  shows the media that comprise the RAID group specified by the RAID group name  1001 . The RAID level  1003  shows the RAID level of the RAID group specified by the RAID group name  1001 . The media type  1004  shows the media type of the RAID group specified by the RAID group name  1001 . The capacity  1005  shows the capacity of the RAID group specified by the RAID group name  1001 .  FIG. 10  shows three sample entries  106 ,  1007 ,  1008 . 
         [0064]      FIG. 11  shows an example of the logical volume information  503 . The logical volume information  503  includes columns of a logical volume name  1101 , a logical volume address  1102 , a RAID group name  1103 , and a RAID group address  1104 . The area specified by the logical volume name  1101  and the logical volume address  1102  is mapped to the area specified by the RAID group name  1103  and the RAID group address  1104 .  FIG. 11  shows three sample entries  1105 ,  1106 ,  1107 . 
         [0065]      FIG. 12  shows an example of the storage pool information  504 . The storage pool information  504  includes columns of a storage name  1201 , a storage pool name  1202 , a logical volume name  1203 , a virtual volume name  1204 , a capacity  1205 , a used amount  1206 , and an available function  1207 . The storage pool information  504  shows that the storage pool name  1202  is located on the storage subsystem specified by the storage name  1201 , comprises the logical volumes specified by the logical volume name  1203 , and has the virtual volumes specified by the virtual volume name  1204 . The capacity  1205  shows the capacity of the storage pool specified by the storage pool name  1202 . The used amount  1206  shows the used amount of the storage pool specified by the storage pool name  1202 . The available function  1207  shows the functions that the storage subsystem can apply to the storage pool specified by the storage pool name  1202 .  FIG. 12  shows two sample entries  1208 ,  1209 . 
         [0066]      FIG. 13  shows an example of the virtual volume information  505 . The virtual volume information  505  includes columns of a virtual volume page number  1301 , a virtual volume name  1302 , a virtual volume address  1303 , a logical volume page number  1304 , a logical volume name  1305 , a logical volume address  1306 , a number of access  1307 , and pinned  1308 . The virtual volume page number  1301  shows the page specified by the virtual volume name  1302  and the virtual volume address  1303 . The logical volume page number  1304  shows the page specified by the logical volume name  1305  and the logical volume address  1306 . The page specified by the virtual volume page number  1301  is mapped to the page specified by the logical volume page number  1304 . The number of access  1307  shows the number of access to the page specified by the virtual volume page number  1301 . The pinned  1308  shows the status whether the page specified by the virtual volume page number  1301  is pinned. If the pinned  1308  is “X”, the page specified by the virtual volume page number  1301  is pinned and the page move program  508  does not move the page to some other tier.  FIG. 13  shows five sample entries  1309 ,  1310 ,  1311 ,  1312 ,  1313 . 
         [0067]      FIG. 14  shows an example of the virtual volume tier policy information  506 . The virtual volume tier policy information  506  includes columns of a volume name  1401  and a tier policy  1402 . The tier policy  1402  shows a policy of the volume specified by the volume name  1401 . When the tier policy  1402  is “AUTO,” frequently accessed pages are moved to a higher tier and rarely accessed pages are moved to a lower tier. When the tier policy  1403  is not “AUTO,” pages are pinned to the tier specified by the tier policy  1402 .  FIG. 14  shows three sample entries  1403 ,  1404 ,  1405 . 
         [0068]      FIG. 15  shows an example of the tier definition information  507 . The tier definition information  507  includes columns of a tier  1501 , a media type  1502 , and a default tier  1503 . The media type  1502  shows the media of the tier specified by the tier  1501 . If the default tier is “X”, the tier specified by the tier  1501  is allocated to unallocated area by the disk control program  501 .  FIG. 15  shows three sample entries  1504 ,  1505 ,  1506 . 
         [0069]      FIG. 16  shows an example of the VM template information  605 . The VM template information  605  includes columns of a template name  1601 , a storage name  1602 , a volume name  1603 , an OS  1604 , and an application  1605 . The VM template information  605  shows volumes in which VM templates are stored and OS and applications that are installed on the templates.  FIG. 16  shows two sample entries  1606 ,  1607 . 
         [0070]      FIG. 17  shows an example of the VM backup information  606 . The VM backup information  606  includes columns of a VM name  1701 , a volume name  1702 , and date and time  1703 . The VM name  1701  shows the name that was backed up. The volume name  1702  shows the volume that stores the backup data. The data and time  1703  shows the date and time that the VM was backed up.  FIG. 17  shows five sample entries  1704 ,  1705 ,  1706 ,  1707 ,  1708 . 
         [0071]      FIG. 18  shows an example of the VM deploy screen  607 . The VM deploy screen  607  includes a VM name  1801 , a template name  1802 , a number of CPU  1803 , a memory  1804 , a storage capacity  1805 , a backup cycle  1806 , a number of generation  1807 , an OK button  1808 , and a cancel button  1809 . An administrator inputs information of a VM to deploy to the management computer  380  with the VM deploy screen  607 . The management computer  380  uses the information to deploy a VM. The VM name  1801  is the name of the VM to deploy. The template name  1802  is a VM template to copy to a VM to deploy. The number of CPU  1803  is the number of CPU of the VM to deploy. The memory  1804  is the capacity of memory of the VM to deploy. The storage capacity  1805  is the capacity of storage of the VM to deploy. The backup cycle  1806  is the backup cycle of the VM to deploy. The number of generation  1807  is the number of the volume of the VM to retain on the storage subsystem. When the administrator clicks the OK buttons  1808 , the management server  380  deploys the VM based on the information on the VM deploy screen  607 . 
         [0072]      FIG. 19  shows an example of the VM restore screen  608 . The VM restore screen  608  includes columns of a VM name  1901 , date and time  1902 , and a restore radio button  1903 , and an OK button  1904  and a cancel button  1905 . An administrator selects the VM that the administrator wants to restore based on the VM name  1901  and the date and time  1902 , clicks the restore radio button  1903 , and clicks the OK button  1904 . 
         [0073]      FIG. 20  shows an example of a VHD read command  2000 . The VHD read command  2000  includes a command type  2001 , a VHD name  2002 , and a VHD address  2003 . The application program  408  sends the VHD read command  2000  to the VHD control program  402  to read the area specified by the VHD name  2002  and the VHD address  2003 . 
         [0074]      FIG. 21  shows an example of a VHD write command  2100 . The VHD write command  2100  includes a command type  2101 , a VHD name  2102 , a VHD address  2103 , and data  2104 . The application program  408  sends the VHD write command  2100  to the VHD control program  402  to write the data specified by the data  2104  to the area specified by the VHD name  2102  and the VHD address  2103 . 
         [0075]      FIG. 22  shows an example of a read command  2200 . The read command  2200  includes a command type  2201 , a volume name  2202 , and a volume address  2203 . The VHD control program  402  sends the read command  2200  to the storage subsystem  360  to read the area specified by the volume name  2202  and the volume address  2203 . 
         [0076]      FIG. 23  shows an example of a write command  2300 . The write command  2300  includes a command type  2301 , a volume name  2302 , a volume address  2303 , and data  2304 . The VHD control program  402  sends the write command  2300  to the storage subsystem  360  to write the data specified by the data  2304  to the area specified by the volume name  2302  and the volume address  2303 . 
         [0077]      FIG. 24  shows an example of a VM deploy command  2400 . The VM deploy command  2400  includes a command type  2401 , a VM name  2402 , a number of CPU  2403 , a memory capacity  2404 , and a volume name  2405 . The management server  380  sends the VM deploy command  2400  to the application server  300  to deploy a VM. The VM name  2402  shows the name of a VM to deploy. The number of CPU  2403  shows the number of CPU of a VM to deploy. The memory capacity  2404  shows the capacity of memory of a. VM to deploy. The volume name  2405  shows the volume name that a VM uses. 
         [0078]      FIG. 25  shows an example of a volume copy command  2500  according to the first embodiment. The volume copy command  2500  includes a command type  2501 , a source volume name  2502 , a destination storage pool name  2503 , and a purpose of copy  2504 . The management server  380  sends the volume copy command  2500  to the storage subsystem  360  to deploy a volume. When the storage subsystem  360  receives the volume copy command  2500 , the storage subsystem  360  creates a volume in the storage pool specified by the destination storage pool name  2503  and copies the volume specified by the source volume name  2502  to the volume that the storage subsystem  360  created. The purpose of copy  2504  shows the purpose to copy a volume. 
         [0079]      FIG. 26  shows an example of a volume copy command reply  2600 . The volume copy command reply  2600  includes a command type  2601  and a new volume name  2602 . The storage subsystem  360  sends the volume copy command reply  2600  to the management server  380 . The new volume name  2602  shows the volume to which the volume specified by the source volume name  2602  is copied. 
         [0080]      FIG. 27  shows an example of a volume delete command  2700 . The volume delete command  2700  includes a command type  2701  and a target volume name  2702 . The management server  380  sends the volume delete command  2700  to the storage subsystem  360  to delete a volume specified by the target volume name  2702 . 
         [0081]    B. Process Flows 
         [0082]      FIG. 28  is an example of a flow diagram showing that the VHD control program  402  receives the VHD read command  2000  or the VHD write command  2100  from the application program  408 , sends the read command  2200  or the write command  2300  to the storage subsystem  360 , and sends the result of read or write to the application program  408 . In step  2801 , the VHD control program  402  receives the VHD read command  2000  or the VHD write command  2100  from the application program  408 . In decision step  2802 , if the command that the VHD control program  402  received in step  2801  is the VHD write command  2100 , then the process goes to decision step  2803 ; if not, then the process goes to step  2806 . In decision step  2803 , if the area specified by the volume address  2103  in the VHD write command  2100  is allocated in the VHD address  702  in the VHD location information  403 , and then the process goes to step  2805 ; if not, then the process goes to step  2804 . In step  2804 , the VHD control program  402  searches unallocated area to any VHDs from the VHD location information  403  and updates the VHD location information  403 . In step  2805 , the VHD control program  402  calculates the volume name  2302  and the volume address  2303  from the VHD name  2102 , the VHD address  2103 , and the VHD location information  403 , sends the write command  2300  to the storage subsystem  360 , and sends the result of write from the storage subsystem  360  to the application program  408 . In step  2806 , the VHD control program  402  calculates the volume name  2202  and the volume address  2203  from the VHD name  2002 , the VHD address  2003 , and the VHD location information  403 , sends the read command  2200  to the storage subsystem  360 , and sends the result of read from the storage subsystem  360  to the application program  408 . 
         [0083]      FIG. 29  is an example of a flow diagram showing that the disk control program  501  receives the read command  2200  or the write command  2300  from the VHD control program  402 , and the disk control program  501  sends the result of read or write to the VHD control program  402 . In step  2901 , the disk control program  501  receives the read command  2200  or the write command  2300  from the VHD control program  402 . In decision step  2902 , if the command that the disk control program  501  received in step  2901  is the write command  2300 , then the process goes to decision step  2903 ; if not, then the process goes to decision step  2906 . In decision step  2903 , if an area specified by the volume name  2302  and the volume address  2303  of the write command  2300  is allocated in the virtual volume information  505 , then the process goes to step  2905 ; if not, then the process goes to step  2904 . In step  2904 , the disk control program  501  allocates an unallocated area of a logical volume for which the media type is specified by the default tier  1503  in the tier definition information  507  to the area specified by the volume name  2302  and the volume address  2303 , and updates the virtual volume information  505 . If the tier policy  1402  of the volume specified by the volume name  2302  is not “AUTO”, then the disk control program  501  updates the pinned  1308  of the page specified by the volume address  2303  to “X.” In step  2905 , the disk control program  501  gets the volume name  2302  and the volume address  2303  from the write command  2300 , gets the logical volume name  1305  and the logical volume address  1306  from the virtual volume information  505 , gets the RAID group name  1003  and the RAID group address  1004  from the logical volume information  503 , and writes the data  2304  in the write command  2300  to the area specified by the RAID group name  1103  and the RAID group address  1104 . In decision step  2906 , if an area specified by the volume name  2202  and the volume address  2203  of the read command  2200  is allocated in the virtual volume information  505 , then the process goes to step  2908 ; if not, then the process goes to step  2907 . In step  2907 , the disk control program  501  returns “0” to the application server  300  because the area specified by the volume name  2202  and the volume address  2203  is not written. In step  2908 , the disk control program  501  gets the volume name  2202  and the volume address  2203  from the read command  2200 , gets the logical volume name  1305  and the logical volume address  1306  from the virtual volume information  505 , gets the RAID group name  1103  and the RAID group address  1104  from the logical volume information  503 , reads the area specified by the RAID group name  1103  and the RAID group address  1104 , and returns the data. In step  2909 , if the command that the disk control program  501  received in step  2901  is the write command  2300 , then the disk control program  501  increments the number of accesses  1306  of the row specified by the volume name  2302  and the volume address  2303  in the write command  2300  by “1,” if not, then the disk control program  501  increments the number of access  1306  of the row specified by the volume name  2202  and the volume address  2203  in the read command  2200  by “1.” 
         [0084]      FIG. 30  is an example of a flow diagram showing the process by which the page move program  508  moves pages. The page move program  508  regularly moves frequently accessed pages to a higher tier and rarely accessed pages to a lower tier. In this embodiment, as defined in the tier definition information  507 , there are three tiers, where tier  1  is the highest tier and tier  3  is the lowest tier. In step  3001 , the page move program  508  gets the number of accesses  1307  from the virtual volume information  505 . In step  3002 , the page move program  508  calculates the capacity in each tier based on the RAID group information  502 , the logical volume information  503 , and the storage pool information  504 , assign pages in decreasing order to tiers in decreasing order except pages for which the pinned  1308  is checked, and decides pages that should be moved to another tier. In step  3003 , the page move program  508  moves the pages that are decided to be moved in step  3002  to the tier specified in step  3002  and updates the virtual volume information  505 . 
         [0085]      FIG. 31  is an example of a flow diagram showing the process by which the VM deploy program  602  deploys a VM when an administrator inputs information about the VM with the VM deploy screen  607  and pushes the OK button  1808 . In step  3101 , the VM deploy program  602  gets the server information  404  from the one or more application servers  300 . In step  3102 , the VM deploy program  602  gets the storage pool information  504  from the one or more storage subsystems  360 . The VM deploy program  602  selects an application server that has CPUs of the number specified by the number of CPU  1803  and selects a memory of the amount specified by the memory  1804  based on the server information  404 , and selects a storage pool that has an amount specified by the storage capacity  1805  and selects a copy or snapshot function based on the storage pool information  504 . In step  3104 , the VM deploy program  602  gets the volume name  1603  of the row in which the entry in the template name column  1601  is the template name  1802 . In step  3105 , the VM deploy program  602  sends the volume copy command  2500  for which the entry in the source volume name column  2502  is the volume name obtained in step  3104 , the entry in the destination storage pool name column  2503  is the storage pool name selected in step  3103 , and the entry in the purpose of copy column  2504  is “DEPLOY” to the storage subsystem  360 . In step  3106 , the VM deploy program  602  receives the volume copy command reply  2600  from the storage subsystem  360 . In step  3107 , the VM deploy program  602  sends the VM deploy command  2400  for which the entry in the VM name column  2402  is the VM name  1801 , the entry in the number of CPU column  2403  is the number of CPU  1803 , the entry in the memory capacity column  2404  is the memory  1804 , and the entry in the volume name column  2405  is the volume name received in step  3106  to the application server  300 . 
         [0086]      FIG. 32  is an example of a flow diagram showing the process by which the VM backup program  603  backs up a VM regularly every backup cycle based on the backup cycle  907  of the VM. In step  3201 , the backup program  603  stops I/O (Input and Output) of the application program  408  running on the VM  406 . In step  3202 , the backup program  603  sends the volume copy command  2500  for which the entry in the source volume name column  2502  is the volume name  905 , the entry in the destination storage pool name column  2503  is the storage pool name that has free space enough to copy the volume, and the entry in the purpose of copy column  2504  is “BACKUP” to the storage subsystem  360 . In step  3203 , the backup program  603  receives the volume copy command reply  2600  from the storage subsystem  360 . In step  3204 , the VM backup program  603  updates the VM backup information  606  based on the VM name, the volume name received in step  3203 , and the date and time. In step  3205 , the backup program  603  restarts I/O of the application program  408 . In step  3206 , the backup program  603  counts the number of backups based on the VM backup information  606 . For example, there are three backups of “VM A.” In decision step  3207 , if the number of backups counted in step  3206  is greater than the number of generation  908 , then the process goes to step  3208 ; if not, then the process ends. In step  3208 , the VM backup program  3208  selects the oldest volume that should be deleted and sends to the storage subsystem  360  the volume delete command  2700  specifying the target volume name  2502  is the volume of the VM selected in step  3208 . 
         [0087]      FIG. 33  is an example of a flow diagram showing the process to be performed when the volume configuration program  509  receives the volume copy command  2500  or the volume delete command  2700  according to the first embodiment. In decision step  3301 , if the volume configuration program  509  receives the volume copy command  2500 , then the process goes to step  3302 ; if not, then the process goes to step  3308 . In step  3302 , the volume configuration program  509  generates a unique name for a new volume, creates the volume on the storage pool specified by the destination storage pool name  2503 , and updates the virtual volume information  505 . In decision step  3303 , if the purpose of copy  2504  is “DEPLOY”, then the process goes to step  3304 ; if not, the process goes to step  3305 . In step  3304 , the volume configuration program  509  adds to the virtual volume tier policy information  506  a row in which the volume name  1401  is the name generated in step  3302  and the tier policy  1402  is “AUTO.” In step  3305 , the volume configuration program  509  adds to the virtual volume tier policy information  506  a row in which the volume name  1401  is the name generated in step  3302  and the tier policy  1402  is “TIER  3 .” In step  3306 , the volume configuration program  509  copies the volume specified by the source volume name  2502  to the volume created in step  3302 . In step  3307 , the volume configuration program  509  sends the volume copy command reply  2600  for which the new volume name  2602  is the volume name generated in  3302  to the management server  380 . In step  3308 , the volume configuration program  509  deletes the volume specified by the target volume name  2702  and updates the virtual volume information  505  and the virtual volume tier policy information  506 . 
       Second Embodiment 
       [0088]      FIG. 34  illustrates an example of the memory  364  in the storage subsystem  360  of  FIG. 3  according to the second embodiment. The memory  364  comprises the disk control program  501 , the RAID group information  502 , the logical volume information  503 , the storage pool information  504 , the virtual volume information  505 , the virtual volume tier policy information  506 , the tier definition information  507 , the page move program  508 , the volume configuration program  509 , a template volume acquisition program  3401 , and a template volume input screen  3402 . 
         [0089]      FIG. 35  shows an example of the template volume input screen  3402  according to the second embodiment. The template volume input screen  3402  includes a template name  3501 , a storage name  3502 , and a volume name  3503 . An administrator inputs information about template volume using the template volume input screen  3402 . The template name  3501  shows a name of a VM template. The storage name  3502  shows the storage subsystem that has a volume that stores the VM template. The volume name  3503  shows the volume that stores the VM template. 
         [0090]      FIG. 36  shows an example of a volume copy command  3600  according to the second embodiment. The volume copy command  3600  is the same as the volume command  2500  in  FIG. 25  except the volume copy command  3600  does not have the purpose of copy  2504 . 
         [0091]      FIG. 37  is an example of a flow diagram showing the process to be performed when the volume configuration program  509  receives the volume copy command  2500  or the volume delete command  2700  according to the second embodiment.  FIG. 37  is similar to  FIG. 33  (first embodiment). Steps  3301 ,  3302 ,  3304 ,  3305 ,  3306 ,  3307 , and  3308  are similar to those of  FIG. 33 . Instead of step  3303 , however,  FIG. 37  has steps  3701  and  3702 . In step  3701 , the template volume acquisition program  3401  gets information about template volumes from the VM template information  605  in the management server  380  or the template volume input screen  3402  input by an administrator. In decision step  3302 , if the source volume name  2502  is same as the volume acquired in step  3701 , then the process goes to  3304  because the purpose of this copy is to deploy; if not, then the process goes to step  3305 . 
         [0092]    Of course, the system configuration illustrated in  FIG. 3  is purely exemplary of information systems in which the present invention may be implemented, and the invention is not limited to a particular hardware configuration. The computers and storage systems implementing the invention can also have known I/O devices (e.g., CD and DVD drives, floppy disk drives, hard drives, etc.) which can store and read the modules, programs and data structures used to implement the above-described invention. These modules, programs and data structures can be encoded on such computer-readable media. For example, the data structures of the invention can be stored on computer-readable media independently of one or more computer-readable media on which reside the programs used in the invention. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include local area networks, wide area networks, e.g., the Internet, wireless networks, storage area networks, and the like. 
         [0093]    In the description, numerous details are set forth for purposes of explanation in order to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that not all of these specific details are required in order to practice the present invention. It is also noted that the invention may be described as a process, which is usually depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. 
         [0094]    As is known in the art, the operations described above can be performed by hardware, software, or some combination of software and hardware. Various aspects of embodiments of the invention may be implemented using circuits and logic devices (hardware), while other aspects may be implemented using instructions stored on a machine-readable medium (software), which if executed by a processor, would cause the processor to perform a method to carry out embodiments of the invention. Furthermore, some embodiments of the invention may be performed solely in hardware, whereas other embodiments may be performed solely in software. Moreover, the various functions described can be performed in a single unit, or can be spread across a number of components in any number of ways. When performed by software, the methods may be executed by a processor, such as a general purpose computer, based on instructions stored on a computer-readable medium. If desired, the instructions can be stored on the medium in a compressed and/or encrypted format. 
         [0095]    From the foregoing, it will be apparent that the invention provides methods, apparatuses and programs stored on computer readable media for tier management to deploy and backup volumes. Additionally, while specific embodiments have been illustrated and described in this specification, those of ordinary skill in the art appreciate that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments disclosed. This disclosure is intended to cover any and all adaptations or variations of the present invention, and it is to be understood that the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with the established doctrines of claim interpretation, along with the full range of equivalents to which such claims are entitled.