Abstract:
In a multi-platform environment, data backup is performed which stores data from various different systems on several storage devices depending on the importance of the data and the reliability level of the backup storage devices. That is, data marked as important is stored on a backup storage device having a high reliability level and less important data is backed up onto a backup storage device having a lower reliability level. This allows the cost performance of the backup system to be optimized.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a data backup method and system, and more particularly, to a data backup method and system in a multi-platform environment. 
     Recently, computer systems having a “multi-platform” environment (or multi-vendor environment), in which computers having various different platforms are connected to a network, are being used. That is, computers having different platforms, such as a mainframe environment, a Unix environment and a Windows NT environment are connected to each other via the network and share data resources. For example, a database installed on a mainframe is accessed by a Unix computer. Unix is a registered trademark in the United States of America and other countries of the X/Open Company Limited, and Windows and Windows NT are registered trademarks of Microsoft Corporation. In such a system, data backup having high cost performance is required. 
     Conventionally, each computer has a backup device handled by the corresponding platform which backs up its data resources. 
     In recent years, distributed processing in which processing is distributed over a plurality of interconnected computers has been widely used. This improves convenience such as ease of changing system functions and human-machine interfaces, and improves reliability, such as localization of the effects of faults. 
     However, backing up data for each computer reduces the backup workability. Therefore, software that collectively controls storage devices (data resources) of a multi-platform environment has been used. For example, the software backs up the data of a whole system onto a tape library device of a mainframe. This is because the tape library device has redundancy and high reliability. 
     However, since the tape library device backs up unuseful data (for example, data used only by an NT client), the capacity of the tape library device must be very large. This increases the cost of the tape library device. That is, bit cost is increased. Further, the ratio of the amount of useful data is low as compared to the amount of storage capacity. Thus, the cost performance of backup is reduced. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a high cost performance data backup system. 
     In one aspect of the present invention a method for saving plural pieces of data of a multi-platform environment on a plurality of storage devices is provided. First, an importance level of each piece of the plural pieces of data and a reliability level of each storage device are set. The plural pieces of data are saved on the plurality of storage devices in accordance with the set importance level and the set reliability level. 
     In another aspect of the present invention, a system for saving plural pieces of data of a multi-platform environment is provided. The system includes a plurality of storage devices each having a reliability level and a setting unit to set an importance level of each piece of the plural pieces of data and a save destination for each piece of the plural pieces of data based on the reliability level of the storage devices. A backup unit is connected between the plurality of storage devices and the setting unit to save the plural pieces of data on the plurality of storage devices in accordance the set importance level and the set save destination. 
     In yet another aspect of the present invention, a computer readable recording medium storing program code for saving plural pieces of data of a multi-platform environment on a plurality of storage devices is provided. The program code comprising the steps of setting an importance level of each piece of the plural pieces of data and a reliability level of each storage device, and saving the plural pieces of data on the plurality of storage devices in accordance with the set importance level and the set reliability level. 
     Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which: 
     FIG. 1 is a schematic block diagram of a server system; 
     FIG. 2 is a schematic block diagram of a computer network including the server system of FIG. 1; 
     FIG. 3 is an illustration of a catalog in accordance with the present invention; 
     FIG. 4 is an illustration of a control data set (CDS) list in accordance with the present invention; 
     FIG. 5 is an illustration of storage in accordance with the present invention; and 
     FIGS.  6 ( a ) and  6 ( b ) are illustrations of a catalog and a CDS list in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 2 is a schematic diagram of a computer network  100 . The computer network  100  is a loop-type and formed by a mainframe  11 , a workstation  12 , an NT server  13  and a server system  14 , and a network  15  interconnecting the mainframe  11 , the workstation  12 , the NT server  13  and the server system  14 . 
     For example, the mainframe  11  uses a predetermined operating system as a platform and has a storage medium (storage) mounted under a predetermined volume name. The workstation  12  uses the Unix operating system as a platform and has a storage medium (storage) mounted under a predetermined volume name. The NT server  13  uses Windows NT as a platform and has a storage medium (storage) mounted under a predetermined volume name. 
     The server system  14  includes a backup storage device which backs up the data handled by the mainframe  11 , the workstation  12  and the NT server  13 . The server system  14  collectively controls the storage of this multi-platform environment. Specifically, the server system  14  performs: 
     Centralized backup of network data; 
     Backup media (tape libraries) management; 
     Automatic scheduling of backup jobs; 
     Hierarchical storage management (HSM); and 
     Database backup. 
     The server system  14  includes a plurality of storage devices having varying levels of reliability. The reliability of a storage device has a correlation with the data bit cost of the storage device. That is, the bit cost of a storage device having high reliability is higher than that of a storage device having low reliability. 
     The server system  14  has an importance level for the storage device of each platform and optimizes an object to be backed up in accordance with the importance level. That is, the data of high importance is stored in a storage device having high reliability and the data of low importance is stored in a storage device having low reliability. This reduces the amount of data stored in the storage device having high reliability compared with that of a conventional storage device. Accordingly, the cost required for backing up all of the data on the computer network  100  is reduced. That is, the cost performance of the data backup system is increased. 
     The server system  14  in the embodiment is implemented with a computer program which is executed on a computer used for a general use, such as a personal computer or a workstation. 
     The computer comprises a processor, a main storage device, an auxiliary storage device and an I/O device and executes the computer program. The computer program is stored on a portable medium, such as a floppy disk or a CD-ROM, and in a main storage device or an auxiliary storage device of another computer connected to the network  15 . 
     The computer program is loaded, copied or otherwise installed from the portable medium onto the main storage device of the computer to the auxiliary storage device, and then to the main storage device. When the computer program is received from another device connected to the network  15 , after it has been received, it is copied or installed on the auxiliary storage device and loaded into the main storage device. 
     Next, the server system  14  is described in detail. 
     FIG. 1 is a schematic block diagram of the server system  14 . The server system  14  comprises an input device  21 , a plurality of backup storage devices  22 ,  23  and  24 , a setting unit  25 , an operating system  26 , a setting storage unit  27  and a backup unit  28 . 
     The first storage device  22  is a tape library device (TL), the second storage device  23  is a magnetic disk drive (D 1 ) and the third storage device  24  is a magnetic disk drive (D 2 ). The first to third storage devices  22  to  24  have different reliability by providing dual storage and/or error correcting and checking codes. In this embodiment, the first storage device  22  has the highest reliability and the third storage device  24  has the lowest reliability. That is, in this embodiment, the first storage device  22  has a dual storage structure and/or stores data with error correcting and checking codes. 
     The input device  21  is used to enter JCL (job control language) or a command by the operator. The operating system  26  activates the setting unit  25  and the backup unit  28  in response to the command provided from the input unit  21 . 
     The setting unit  25  sets a software attribute (importance level of data or file) and a hardware attribute (reliability level of a backup storage device) in the setting storage unit  27  in accordance with the input command and data (either input with the command or preset). 
     The setting storage unit  27  has an area for storing a catalog  29  and a control data set (CDS) list  30  in which the data attribute and the hardware attribute for all of the data on the network  15  are set. A software attribute (data importance level) is set in the catalog  29  and the hardware attribute (reliability level of a backup storage device) in the CDS list  30 . 
     Specifically, the catalog  29 , as shown in FIG. 3, has areas for storing the location (volume name) in which a file exists, its file name and the importance of the file. The CDS list  30 , as shown in FIG. 4, has areas for storing a file name and its save location (backup media). 
     The save location is set so that a file having high importance is backed up in a storage device having high reliability, based on the reliability levels and the importance levels, to thereby optimize the safety of an object to be backed up. 
     The backup unit  28  selectively saves the data stored in a disk drive  11   a  of the mainframe  11 , the data stored in a disk drive  12   a  of the workstation  12 , and the data stored in a disk drive  13   a  of the NT server  13  to the first to third storage devices  22  to  24  (i.e., the tape library (TL) and the disk drives D 1 , D 2 ) in accordance with the importance levels based on the information of the catalog  29  and the CDS list  30 . 
     Next, the backup of the data by the server system  14  is described in accordance with FIG.  5  and FIG.  6 . 
     Now, as shown in FIG. 5, the disk drive  11   a  of the mainframe  11  is located under volume name V 01  and the disk drive  11   a  stores files to which file names FA 1 , FA 2  and FA 3  are attached, respectively. The disk drive  12   a  of the workstation  12  is located under volume name V 02  and the disk drive  12   a  stores files to which file names FB 1 , FB 2  and FB 3  are attached, respectively. The disk drive  13   a  of the NT server  13  is located under volume name V 03  and the disk drive  13   a  stores files to which file names FC 1 , FC 2  and FC 3  are attached, respectively. 
     The operating system  26  of FIG. 1 activates the backup unit  28  in response to a backup start command input via the input unit  21 , for example after finishing routine work. 
     First, the backup unit  28  backs up a file having high importance in the first storage device  22  having high reliability in accordance with the importance information of the catalog  29 . That is, the backup unit  28  backs up the files FA 1 , FA 2 , FB 1  and FC 1  of importance level 1 in the first storage device  22  (tape library TL) whose reliability level is highest. Further, the backup unit  28  backs up the files FA 3  and FB 2  of importance level 2 in the second storage device  23  (disk drive D 1 ) whose reliability level is next highest. Finally, the backup unit  28  backs up the files FB 3 , FC 2  and FC 3  of importance 3 in the third storage device  24  whose reliability level is lowest. 
     As described above, the embodiment has the following advantages. 
     The server system  14  manages a hardware attribute and a data attribute using the catalog  29  and the CDS list  30  and then executes back up with high cost performance. 
     It should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the invention may be embodied in the following forms. 
     (1) The server system  14  may collectively control all types of storage including a storage of another computer connected to the network including the mainframe  11 , the workstation  12 , and the NT server  13 . Further, the server system  14  may back up data stored in a storage device connected to a network and accessed from each platform. 
     (2) The number of importance levels to be set and the number of storage devices may be changed. For example, two or four or more importance levels can be set. Further, a server system having the first and second storage devices  22  and  23  of FIG.  1 . may be formed. In this case, the save location is changed in accordance with the capacities of the storage devices. For example, the file of importance level 1 is backed up on the first storage device  22  and the files of importance levels 2 and 3 are backed up on the second storage device  23 . Alternatively, the files of importance levels 1 and 2 are backed up in the first storage device  22  and the file of importance level 3 is backed up in the second storage device  23 . 
     (3) The present invention may be adapted to a computer network, such as a bus type, a ring type, a star type, a mesh type and a point-to-point type. Both wire and wireless data communication can be used. 
     (4) The present invention may be adapted to another connection, such as an online connection in which a plurality of computers interconnected. 
     (5) The importance information and the backup media may be set in units of volume. In this case, a volume name, importance information and backup madia are set in the catalog  29  and the CDS list  30 . This reduces the person-hours of work by setting the collective backup of a plurality of files. 
     (6) The file may be backed up in accordance with a operational speed of a storage device. The operational speed corresponds to the reliability of the storage device. That is, a storage device having a fast operational speed (read and write speed) has a high reliability and the bit cost of the data stored in the storage device is higher than that of a storage device whose operational speed is slow. Thus, high cost performance backup is achieved. 
     Therefore, the present examples and the embodiment are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.