JP2006277355A - Path switching system and method for backup system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a path switching function for a virtual tape library. <P>SOLUTION: A backup server 10 includes a plurality of systems of paths 104 and 105 to a virtual tape library device 300 and path switching software 102 performing switching of the paths, in which write data is transferred to the virtual tape library device 300 after copying to a built-in disk 103 that is a temporary storage area, and the write data copied in the temporary storage area is deleted when a report of write completion of file mark is received for a file mark write instruction from the backup software 101. Further, in the event of path failure, switching of the paths is performed, a virtual tape is repositioned to a write restart position, and data copied in the temporary storage area is rewritten thereto, whereby the function capable of shielding the backup software 101 from path failure to continue backup even in the event of path failure is supported. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a path switching method of a data backup system using a virtual tape library, and particularly when a failure occurs in a data transfer path between a backup server and a virtual tape library apparatus or a controller of a virtual tape library apparatus. The present invention relates to a path switching system and a path switching method of a backup system that can easily switch paths.

  In a conventional computer system, a tape library system including a magnetic tape device as a storage device for data backup using the characteristics of the magnetic tape device having a large storage capacity and the property of the magnetic tape having a low bit unit price, and the tape A backup system comprising a library server and a backup server controlled by backup software has been adopted.

  In addition, in order to cope with the occurrence of a path failure between the application server and the disk device, by incorporating path switching software in the application server, even if a path failure occurs, the application program is shielded from the path failure and another path However, the backup system has a problem that the backup cannot be continued if a path failure occurs because the path switching software does not support the magnetic tape device.

  On the other hand, along with the recent increase in storage capacity of magnetic disk devices and the lowering of the unit price per bit, a backup system using a magnetic disk device as a backup data storage destination has been operated as a data backup system in order to shorten the backup time. Yes. In this backup system using a magnetic disk device, there are two methods: a method using a virtual tape library device emulating a magnetic tape library device using a magnetic disk, and a D2D method for backing up to a magnetic disk device with backup software. Is common.

Note that the following patent documents are listed as documents describing the technology related to the backup system as described above.
JP 2004-326638 A JP 2003-208362 A JP 2003-44310 A JP 2002-91938 A JP 2001-290669 A JP-A-11-353292 JP-A-11-175488

  The above-described backup system using a magnetic tape as a recording medium has a problem that it is difficult to perform path switching at the time of the path failure because a sequential recording / reproducing magnetic tape is used as the recording medium. In other words, since the magnetic disk device is a direct access device, it is sufficient to rewrite the data of the failed block from another path, whereas in a backup system using a magnetic tape as a recording medium, the physical path is utilized by using another path. After repositioning the previous file mark on the magnetic tape, it is necessary to rewrite the data after the previous file mark, and this processing takes several minutes of processing time. There is a possibility that a timeout which is a predetermined processing time limit may occur, and there is a problem that path switching cannot be performed practically.

  On the other hand, in the D2D method of backing up to a magnetic disk device with backup software, the path switching software for the magnetic disk device can be used, whereas the virtual tape library system emulating a magnetic tape library device using a magnetic disk is a tape Although the medium can be easily replaced with an existing magnetic tape library device by emulating the medium, there is a problem that the path switching software cannot be applied as in the magnetic tape library device.

  An object of the present invention is to eliminate the problems caused by the above-described conventional technology, and to provide a path switching system and a path switching method for a backup system that can easily perform path switching in a virtual tape library system. .

In order to achieve the above object, the present invention provides a path switching system for a backup system in which backup of data is controlled by a backup server for a virtual tape library device in which a magnetic tape is virtualized by a magnetic disk.
The backup server includes a virtual tape library apparatus, a plurality of paths, and path switching software for switching the paths, and the path switching software copies the write data to the temporary recording area and then transfers the write data to the virtual tape library apparatus. And forward to
Transfer the file mark write instruction from the backup software to the virtual tape library device, and erase the write data copied to the temporary recording area when receiving a report of the completion of writing the file mark from the virtual tape library device,
When a path failure occurs, the path is switched, a rewind command for instructing rewinding of the magnetic tape medium through the switched path, and a report of the completion of rewind in response to the rewind command. When receiving, the write command stored in the temporary recording area is written to the virtual tape library device when the positioning command for positioning the tape to the previous file mark and the positioning completion command in response to the positioning command are received. The first feature is to operate so as to issue a command.

The present invention also relates to a path switching system for a backup system in which backup of data is controlled by a backup server for a virtual tape library device in which a magnetic tape is virtualized by a magnetic disk.
The backup server is
Including a virtual tape library device and a path switching software for switching between a plurality of paths and the path, and the path switching software transfers the write data to the temporary recording area and then transfers the write data to the virtual tape library device.
Transfer the file mark write instruction from the backup software to the virtual tape library device, and erase the write data copied to the temporary recording area when receiving a report of the completion of writing the file mark from the virtual tape library device,
The virtual tape library device supports the vendor unique command that positions the next block after the last written block and reports the block number of the write start from the previous file mark.
When a path failure occurs, the backup server switches the path, issues the vendor unique command to the virtual tape library device, and receives the report of the write start block number from the vendor unique command. The second feature is that it operates so as to issue a command to write to the virtual tape library device from the block next to the last written block of the write data stored in the recording area.

Furthermore, the present invention relates to a path switching method for a backup system in which backup of data is controlled by a backup server for a virtual tape library device in which a magnetic tape is virtualized by a magnetic disk.
The backup server is provided with a virtual tape library device, a plurality of paths, and path switching software for switching the paths,
A step of transferring the write data to the virtual tape library device after copying the write data to the temporary recording area; a step of transferring a file mark write instruction from the backup software to the virtual tape library device; Performing a process of erasing the write data copied to the temporary recording area when receiving a report of completion of writing the file mark;
When a path failure occurs, the step of switching the path, the step of issuing a rewind command for instructing the rewinding of the magnetic tape medium through the switched path, and responding to the rewind command When a rewind completion report is received, a positioning command for positioning the tape to the previous file mark is issued, and when a positioning completion command in response to the positioning command is received, the tape is stored in the temporary recording area. A third feature is that a step of issuing a command for writing the written data to the virtual tape library apparatus is executed.

The present invention also provides a path switching method for a backup system in which a backup server controls data backup for a virtual tape library device in which a magnetic tape is virtualized by a magnetic disk.
The backup server is provided with a virtual tape library device, a plurality of paths, and path switching software for switching the paths,
A step of transferring the write data to the virtual tape library device after copying the write data to the temporary recording area; a step of transferring a file mark write instruction from the backup software to the virtual tape library device; Performing a process of erasing the write data copied to the temporary recording area when receiving a report of completion of writing the file mark;
Let the virtual tape library device support a vendor unique command that positions the block next to the last written block and reports the write start block number from the previous file mark,
When a path failure occurs, the process of switching the path, the process of issuing the vendor unique command to a virtual tape library apparatus, and the temporary block when receiving a write start block number report from the vendor unique command A fourth feature is that a step of issuing a command to write to the virtual tape library apparatus from the block next to the last written block of the write data stored in the recording area is executed.

  In the backup system path switching system and method according to the present invention, the path fault is blocked in the backup software of the backup server, and the path switching software copies the write data between the file marks to the temporary recording area, and the path fault occurs. Sometimes, path switching can be easily performed even in a virtual tape library system by executing path switching / repositioning / rewriting processing. Furthermore, the path switching system and method according to the present invention allows the virtual tape library device to support a vendor unique command that positions the block next to the last written block and reports the write start block number from the previous file mark, The path switching software can shorten the processing time for repositioning and data rewriting after path switching by issuing the vendor unique command.

  Hereinafter, a backup system to which a backup system path switching method according to an embodiment of the present invention is applied will be described in detail with reference to the drawings. 1 is an overall configuration diagram of a backup system for a virtual tape library according to the present embodiment, FIG. 2 is a diagram for explaining data write processing in the backup system, and FIG. 3 is for explaining file mark write processing. FIG. 4, FIG. 4 is a diagram for explaining retry processing when a path failure occurs, FIG. 5 is a diagram for explaining retry processing when a path failure occurs when vendor unique commands are supported, and FIG. 6 shows the processing procedure of the path switching software. FIG. 7 is a diagram showing a write processing procedure in this system, FIG. 8 is a diagram showing file mark processing in this system, and FIG. 9 is a diagram showing read processing in this system.

  As shown in FIG. 1, the backup system according to the present embodiment is connected to a host computer (not shown), and is connected to a disk array device 200 that stores data to be backed up. Two FC (fiber channel) switches 201 and 202 are connected. And a virtual tape library device 300 that backs up data via the FC switch 201 or 202, and a backup server 100 that performs backup control of data from the disk array device 200 to the virtual tape library device 300. . The backup server 100 may be composed of a plurality of units.

  The backup server 100 includes FC HBAs (fiber channel host bus adapters: paths) 104 and 105 connected to the FC switches 201 and 202, path switching software 102 for switching between the FC HBAs 104 and 105, the path It includes a built-in disk 103 connected to the switching software 102 and backup software 101 for performing data backup control, and the backup software 101 is configured to switch the paths of the FC HBAs 104 and 105 via the path switching software 102. .

  The virtual tape library device 300 includes virtual tape library controllers (VTL controllers) 301 and 303 provided for the FC switches 201 and 202, and a backup destination disk array device 302 connected to the VTL controllers 301 and 303. Backup data is backed up from the disk array device 200 to the disk array device 302 via the VTL controller 301 or 303 and the FC switch 201 or 202.

  The backup software 101 of the backup server 100 performs a process of writing a file mark (corresponding to a gap between data on the magnetic tape) between the backup data for each backup data of 1 GB to 2 GB, for example, at the time of the data backup. Execute. In addition, the path switching software 102 is configured to make the backup software 101 appear to have only one path and shield the error report at the time of the path failure.

The internal recording disk 103 may be used as the temporary recording area for copying the write data between the file marks, and for example, a part of the backup target disk array device 200 may be used.
<Data write processing>

The backup system configured as described above, when writing write data a (WR1, WR2, WR3, WR4) to the virtual tape library device 300 as shown in FIG. 2, stores the block WR1 of this write data a in a temporary recording area. Is temporarily stored as data save b in the internal disk 103, and then transferred to the virtual tape library apparatus 300 as write data c via the FC HBA 104, and subsequently to the blocks WR2, WR3, and WR4 of the write data a. It operates so as to be transferred to the virtual tape library device after being saved in the temporary recording area.
<File mark write processing>

As shown in FIG. 3A, the file mark writing process performed during the data backup process is performed by issuing a file mark writing instruction e via the FC HBA 104 according to the instruction d from the backup software 101, and the file mark writing is completed. A write OK response f to that effect is returned, and as shown in FIG. 3B, the write data a stored in the built-in disk 103, which is a temporary recording area, is deleted g according to the response f.
<Retry processing for path failure 1>

  Further, as shown in FIG. 4A, the backup system according to the present embodiment performs an error report response after issuing the write instruction for the write data a, the data save b for the write data a, and the write instruction for the write data c. If h exists, as shown in FIG. 4B, the path switching software 102 switches the path to the FC HBA 105 and (1) the file before the error occurs because the recording unit of the magnetic tape is one block unit. A rewind command j for rewriting data from the mark position, (2) a response k indicating that the rewind has been completed in response to this command, and (3) positioning the magnetic head at the previous file mark. A command m, (4) a response l (el) indicating that positioning of the magnetic head of the magnetic tape has been completed in response to this command, (5) a command n instructing writing of write data, and (6 The data write retry operation is performed by sequentially executing a response o indicating that the write has been completed in response to this command.

That is, when a path failure occurs, the backup system according to the present embodiment performs the rewinding of the magnetic tape / positioning to the previous file mark in the same manner as the processing for the magnetic tape as the target of the recording medium. By operating so as to rewrite data, path switching can also be performed for the virtual tape library apparatus.
<Retry processing for path failure 2>

  Furthermore, in the backup system according to the present embodiment, when the path switching software 102 has a vendor unique command that can be set unique to the software, and the virtual tape library apparatus 300 supports the vendor unique command, FIG. As shown in FIG. 5, when there is a write instruction for the write data a / data save b / error report response h, the path switching software 102 switches the path to the FC HBA 105 as shown in FIG. 1) The backup software 101 has a write restart position inquiry command p that is a vendor unique command, (2) a write restart position report q (for example, a WR7 restart position report) for this command, and (3) built-in in response to this report Process i for reading write data from the disk 103, and (4) writing the write data And no command r, (5) by sequentially executing a response s of the writing has been completed for this command, the retry operation of the data writing.

  That is, when the backup system according to the present embodiment supports the vendor unique command, the data switching retry operation can be easily performed on the virtual tape library apparatus 300 by issuing the vendor unique command from the path switching software 102. it can.

In particular, in the present embodiment, for example, when 2 GB data exists in the internal disk 103 which is a temporary recording area, when a magnetic tape is used as a recording medium, it takes several minutes to rewind and reposition the tape. Assuming that the data transfer rate is 40 MB / s, the rewriting processing time of 50 seconds is required. In the virtual tape library, the rewinding and repositioning of the tape is completed in 1 second or less, and then the data transfer rate is 160 MB. It was expected that the rewrite processing time could be shortened to 12.5 seconds because it can be expected to be greater than / s, but with the support of the vendor unique command, the rewrite processing time varies depending on the location of the failure, but the average 1 / 2 to 6.3 seconds.
<Process of path switching software>

Next, switching processing of the FC HBAs 104 and 105 by the path switching software 102 will be described with reference to FIG. In this process, first, when the path switching processing software 102 receives a command from the backup software 101 (step 601), it is determined whether or not the received command is a write command (step 602). When the designated write process (step 603) is executed and it is determined that the command is not a write command, it is determined whether or not the command is a file mark command (step 604). A mark writing process (step 607) is executed, and if it is determined that it is not a file mark command, a command is issued (step 608), and then it is determined whether or not a path failure has occurred in the issued command (step 609). If the path is not faulty, the process ends and the path fault Operates so as to end the process path switching described above (step 610) and re-issue the command (step 611) if it is.
<Light processing procedure>

  The write processing by the backup system in step 602 of FIG. 6 will be described with reference to FIG. 7 taking as an example the case where the vendor unique command is supported. As shown in FIG. 7, the write processing is performed by the backup software 101 first copying and saving one block data of the write data to the internal disk 103 as a temporary recording area (step 702) and then writing the one block data. (Step 703) is performed, and then it is determined whether or not a path failure has occurred (Step 704). The block is a unit of writing when a magnetic tape is used as a medium.

  If it is not determined in step 704 that there is a path failure, it is determined whether or not there is an error (step 705), and if there is no error, it is determined whether or not the write processing for all blocks has been completed (step 706). If it is determined that the writing has been completed, the process is terminated.

On the other hand, when it is determined in step 704 that a path failure has occurred, this processing is performed for path switching (step 707), write resumption position inquiry (step 708), and write resumption position as described above. Data is rewritten from the internal disk 103, which is a temporary recording area (step 709), whether or not there is an error (step 710), and if there is no error, it is determined whether or not all blocks have been written (step). 711), and when it is determined that all blocks have been written, the process ends.
<File mark processing>

The file mark processing by the backup system in step 605 of FIG. 6 will be described with reference to FIG. As shown in FIG. 8, the file mark process includes a process for writing a file mark as described above (step 802), a process for determining whether or not a path failure has occurred (step 803), and a path failure based on the determination. In the case where no data is detected, a process of deleting the saved data of the internal disk 103 is performed (step 806). When a path failure occurs in the step 803, a path switching process (step 804) and a file mark writing process (step 806) are performed. Step 805) is performed, and then the process of proceeding to Step 806 is sequentially executed.
<Read processing>

  The read processing by the backup system in step 607 of FIG. 6 will be described with reference to FIG. In this read process, as shown in FIG. 9, the backup software 101 reads one block of data from the virtual tape library device 300 (step 902), and then determines whether or not a path failure has occurred (step 903). If it is not determined that there is a path failure, the presence / absence of an error is determined (step 904), and if there is no error, it is determined whether or not the read processing for all blocks has been completed (step 905), and the reading of all blocks is completed. If it is determined that the process has been completed, the process is terminated.

  When it is determined in step 903 that a path failure has occurred, this processing is performed by switching the path (step 906), issuing a command for resuming the read resumption position (step 907), and performing one block after the positioning. Data reading processing (step 908) and the presence / absence of error (step 909) are performed, and if there is no error, it is determined whether or not the reading processing of all blocks has been completed (step 910). If it is determined that the reading has been completed, the process is terminated.

  As described above, according to the present embodiment, the backup software is configured to execute the above-described data write process / file mark write process / retry operation, so that path switching can be easily performed even in the virtual tape library system. .

1 is an overall configuration diagram of a backup system according to an embodiment of the present invention. The figure for demonstrating the data write process of this system. The figure for demonstrating the file mark write process of this system. The figure for demonstrating the retry process at the time of the path | pass failure of this system. The figure for demonstrating the retry process at the time of the path | pass failure at the time of vendor unique command support of this system. The figure which shows the process sequence of the path switching software by this embodiment. The figure which shows the write-processing procedure by this embodiment. The figure which shows the file mark process by this embodiment. The figure which shows the read process in this embodiment.

Explanation of symbols

100: backup server 101: backup software 102: path switching software 103: internal disk 104: FC HBA (path) 200: backup target disk array device 201: switch 300: virtual tape library device 301: Controller 302: Backup destination disk array device.

Claims (4)

A backup system path switching system in which a backup server controls data backup for a virtual tape library device in which magnetic tape is virtualized by a magnetic disk,
The backup server is
Including a virtual tape library device and a path switching software for switching between a plurality of paths and the path, and the path switching software transfers the write data to the temporary recording area and then transfers the write data to the virtual tape library device.
Transfer the file mark write instruction from the backup software to the virtual tape library device, and erase the write data copied to the temporary recording area when receiving a report of the completion of writing the file mark from the virtual tape library device,
When a path failure occurs, the path is switched, a rewind command for instructing rewinding of the magnetic tape medium through the switched path, and a report of the completion of rewind in response to the rewind command. When receiving, the write command stored in the temporary recording area is written to the virtual tape library device when the positioning command for positioning the tape to the previous file mark and the positioning completion command in response to the positioning command are received. A backup system path switching system that operates to issue commands. A backup system path switching system in which a backup server controls data backup for a virtual tape library device in which magnetic tape is virtualized by a magnetic disk,
The backup server includes a virtual tape library apparatus, a plurality of paths, and path switching software for switching the paths, and the path switching software copies the write data to the temporary recording area and then transfers the write data to the virtual tape library apparatus. And forward to
Transfer the file mark write instruction from the backup software to the virtual tape library device, and erase the write data copied to the temporary recording area when receiving a report of the completion of writing the file mark from the virtual tape library device,
The virtual tape library device supports the vendor unique command that positions the next block after the last written block and reports the block number of the write start from the previous file mark.
When a path failure occurs, the backup server switches the path, issues the vendor unique command to the virtual tape library device, and receives the report of the write start block number from the vendor unique command. A path switching system for a backup system, characterized in that it operates so as to issue a command to write to a virtual tape library device from a block next to a last written block of write data stored in a recording area. A backup system path switching method in which a backup server controls data backup for a virtual tape library device in which a magnetic tape is virtualized by a magnetic disk.
The backup server is provided with a virtual tape library device, a plurality of paths, and path switching software for switching the paths,
A step of transferring the write data to the virtual tape library device after copying the write data to the temporary recording area; a step of transferring a file mark write instruction from the backup software to the virtual tape library device; Executing a step of erasing the write data copied to the temporary recording area when receiving a report of completion of writing the file mark,
When a path failure occurs, the step of switching the path, the step of issuing a rewind command for instructing the rewinding of the magnetic tape medium through the switched path, and responding to the rewind command When a rewind completion report is received, a positioning command for positioning the tape to the previous file mark is issued, and when a positioning completion command in response to the positioning command is received, the tape is stored in the temporary recording area. And a step of issuing a command for writing the write data to the virtual tape library apparatus. A backup system path switching method in which a backup server controls data backup for a virtual tape library device in which a magnetic tape is virtualized by a magnetic disk.
The backup server is provided with a virtual tape library device, a plurality of paths, and path switching software for switching the paths,
A step of transferring the write data to the virtual tape library device after copying the write data to the temporary recording area; a step of transferring a file mark write instruction from the backup software to the virtual tape library device; Executing a step of erasing the write data copied to the temporary recording area when receiving a report of completion of writing the file mark,
Let the virtual tape library device support a vendor unique command that positions the block next to the last written block and reports the write start block number from the previous file mark,
When a path failure occurs, the backup server receives a report of the path switching process, a process of issuing the vendor unique command to the virtual tape library device, and a write start block number from the vendor unique command. A backup system path switching method characterized by executing a step of issuing a command to write to a virtual tape library device from a block next to a last written block of write data stored in the temporary recording area.

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