JP2004171145A - Virtual tape backup system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a virtual tape backup system for reducing an empty area. <P>SOLUTION: This virtual tape backup system controls one backup as one virtual tape of setting a tape number, and is provided with an address of a storage area of a virtual magnetic tape storage device 30 and an area control table 221 for storing tape information composed of an index with every tape number or the tape number or a T terminal signal with every tape number or the empty area in response to the address. When backing up data, data capacity with every virtual tape can be varied by referring to address corresponding tape information stored in the area control table 221. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a virtual tape backup system that stores data by imagining a magnetic disk on a magnetic tape, and more particularly to a virtual tape backup system that can efficiently back up data of a computer system.
[0002]
[Prior art]
Generally, computer systems tend to be enormous in system and data, and it is essential to back up data and the like in preparation for a data failure due to a disaster or the like. Conventionally, a backup system according to the prior art has a low cost per bit of a magnetic tape compared with a cost per bit of a magnetic disk. Therefore, a backup system using a magnetic tape storage device and a backup control device that controls the backup of data and the like to the magnetic tape storage device. Backup system was used.
[0003]
However, in recent backup systems, when a magnetic tape is used, the data transfer speed is slow, the backup time is redundant, and in recent years, the bit unit price of the magnetic disk has rapidly decreased, so that the What is used as a backup medium is realized, and this backup system is referred to as a virtual tape backup system in this specification. This backup system emulates a virtual tape storage device as a backup target of a conventional magnetic tape storage device from the viewpoint of a computer system, and backs up data. The data to be backed up may be sequential data compressed on the system.
[0004]
Documents describing the technology relating to the virtual tape backup system as described above include, for example, JP-A-3-304926, JP-A-6-252221, and JP-A-9-96543.
[0005]
[Problems to be solved by the invention]
The virtual tape backup system as described above emulates a magnetic disk as a magnetic tape as described above, and divides and secures the capacity of each magnetic tape winding on the magnetic disk. The number of magnetic tape windings that can be generated has been limited to the total capacity obtained by adding up the capacity of each magnetic tape winding.
[0006]
However, in the conventional backup system, since the tape capacity with an extra margin for backup is set at the time of system design, the entire capacity is not used for the reserved virtual tape capacity, and the free space is not used. This inevitably occurs, causing a problem that it is difficult to efficiently use the entire capacity of the magnetic disk.
[0007]
This will be described with reference to the drawings. As shown in FIG. 4, when three virtual magnetic tapes are set for the entire magnetic disk capacity, as shown in FIG. When the first to third virtual tape capacities having signals are secured, and then the first data is 30 GB, the second data is 20 GB, and the third data is 25 GB as shown in FIGS. This causes a problem that an unused space area of about 10 GB, 20 GB, 15 GB, and a total of about 45 GB is generated for each virtual magnetic tape.
[0008]
Further, in a backup system using a virtual magnetic tape according to the related art, data may be lost if a virtual tape operation error occurs when multiple backups are performed on a single virtual magnetic tape in a write-once format. However, there is a problem that data for several generations may be lost.
[0009]
Also, as shown in FIG. 5A, three virtual magnetic tapes are secured for the total magnetic disk capacity, and the first to third virtual tape capacities having a T termination signal at the end of each 40 GB are secured. Next, as shown in FIG. 5 (b), the first data of 30 GB is backed up to the first one, and as shown in FIG. 5 (c), the 30 GB first magnetic data is transferred from the remainder of the first virtual magnetic tape to the middle of the second one. FIG. 5D shows a case in which a backup of the second generation data is performed, and then a backup of the third generation data of 30 GB is performed from the middle of the second virtual magnetic tape to the middle of the third virtual magnetic tape. ), The first-generation new data is written to the third virtual magnetic tape, the old first-generation data remains, and the old first-generation data area and the free area have one tape area. As well as other virtual tapes Generation there has been a problem that you say that you can not.
[0010]
It is also conceivable to set the capacity of one virtual magnetic tape to a small value. In this case, however, the end position information called EOT allocated to the end of the virtual magnetic tape is detected, and the waiting for insertion of the next magnetic tape is started. There is a problem that the state or abnormal termination may occur.
[0011]
SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art, and to provide a virtual tape backup system that can efficiently use the entire capacity of a magnetic disk. A virtual tape backup that prevents a new virtual magnetic tape from being created even though a new virtual magnetic tape can be created without using up magnetic disk capacity and prevents abnormal termination Is to provide a system.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a virtual magnetic tape storage device for storing backup data and a backup control device for controlling backup of the virtual magnetic tape storage device. A virtual tape backup system for controlling as a virtual tape, wherein the backup control device is configured to control an address of a storage area of the virtual magnetic tape storage device and an index for each tape number or a tape number or a tape number for each of the addresses. An area management table for storing tape information including a T-termination signal or an empty area is provided, and at the time of data backup, the data capacity of each virtual tape can be changed by referring to the address corresponding tape information stored in the area management table. This is a first feature.
[0013]
Further, according to the first aspect, in the first aspect, when overwriting one virtual tape data, after releasing the data previously stored in the virtual magnetic tape storage device and the T-termination signal, the data is stored in the released empty storage area. A second feature is that the overwriting data is written, a T end signal is written at the end of the overwriting data, and the tape information stored in the area management table is rewritten corresponding to the address where the overwriting data and the T end signal are stored, In the second aspect, when one piece of virtual tape data is subdivided in the storage area by writing the overwrite data, the data is rearranged so that the one piece of virtual tape data is continuous in the storage area. Performing is a third feature.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a virtual tape backup system according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual diagram illustrating the overall configuration of a backup system according to the present embodiment, FIG. 2 is a diagram illustrating a data backup procedure according to the present embodiment, and FIG. 3 illustrates an area management table according to the present embodiment. FIG.
[0015]
First, as shown in FIG. 1, a virtual tape backup system according to the present embodiment includes a backup control device 20 connected to a backup target server 10 which is a computer system that requires data backup, and a backup control device 20 A virtual magnetic tape storage device 30, which is a storage device for backing up data under control.
[0016]
The virtual magnetic tape storage device 30 has a built-in magnetic disk as a storage medium, and the backup control device 20 has an interface control unit 23 for transmitting and receiving data to and from the virtual magnetic tape storage device 30, and a virtual magnetic tape storage device. An area management / control unit 22 for managing and controlling the recording area and a controller 21 for controlling the whole of them are provided on a unit 30, and one backup is managed as one tape. Further, the area management / control unit 22 includes an area management table 221 for storing a pointer (address) / tape number / order in a storage area of the magnetic disk.
[0017]
In the example shown in FIG. 1, the area management table 221 stores the index of the tape 1 in the pointer (magnetic disk address) 1, stores the index of the tape 2 in the pointer 2, and stores the index of the tape 3 in the pointer 3. The index is stored, the data of the tape 1 is stored in the pointer 4, the data of the tape 1 is stored in the pointer 5,..., The T end signal (EOT) indicating the end position of the tape 1 is stored in the pointer n + 1. And details will be described later. Incidentally, the tape 1 means a virtual first tape generated at the time of the first backup, and the tape 2 means a virtual second tape generated at the time of the next backup. .
[0018]
In the virtual tape backup system configured as described above, the backup control device 20 sequentially backs up various data recorded in the backup target server 10 to the magnetic disk medium of the virtual magnetic tape storage device 30. The procedure for writing the backup data to the magnetic disk medium will be described with reference to FIGS.
[0019]
The rectangles shown in FIGS. 2A to 2G are virtual illustrations of a storage area of a magnetic disk medium, and an example in which data is backed up by imagining a storage area of a magnetic tape with respect to this storage area. explain.
[0020]
First, in the virtual tape backup system according to the present embodiment, as shown in FIG. 2A, the index of the first / second / third tape is written to addresses 1 to 3 by the controller 21 of the control device 20. At this time, the present system stores, in the area management table 221, the fact that the data (contents are indexes) of the tapes 1 to 3 has been written to the addresses 1 to 3, as shown in FIG.
[0021]
Next, in the present system, the controller 21 writes 30 GB data in the storage area of the first tape as shown in FIGS. 2B to 2C, and at the data end position, as shown in FIG. 3A, the fact that the data of the tape 1 has been written is stored in the area management table 221 at addresses 4, 5,... As shown in FIG. 3B, and the T end signal of the tape 1 is stored in the address n + 1. Store.
[0022]
Next, when writing the second and third data, the system writes 20 GB data in the storage area of the second tape, sets the T end signal at the data end position as shown in FIG. Following the T end signal of the second tape, data recording of the third 25 GB data is started from the remaining area of the second tape, recorded on the tape of the third tape, and the T end signal is set. At this time, the system stores the fact that the data of the tape 2 has been written in the area management table 221 at address n + 2... As shown in FIG. A signal is set, the fact that the data of the tape 3 has been written is set at addresses n + a + 2, 2n..., And the T end signal of the tape 3 is stored at address 2n + b + 1.
[0023]
As described above, in the backup system according to the present embodiment, the area management / control unit 22 of the backup control device 20 stores the index for each tape in the area management table 221 and writes and reads data for each volume as viewed from the system side. Data backup corresponding to one tape is performed by setting a T-termination signal for each winding, and this operation is viewed from the system side to back up data for each winding, so that no extra free space is generated. Thus, the entire capacity of the magnetic disk can be used efficiently.
[0024]
That is, in this embodiment, in a virtual tape backup system in which one backup is controlled as one virtual tape with a tape number set, the backup control device determines the address of the storage area of the virtual magnetic tape storage device and the corresponding address. An area management table for storing an index for each tape number or a tape information comprising a tape number or a T end signal for each tape number or an empty area is provided, and at the time of data backup, the tape information corresponding to the address stored in the area management table is stored. By referencing, by making the data capacity of each virtual tape variable, it is possible to efficiently use the entire capacity of the magnetic disk without generating extra free space.
[0025]
Next, an example in which data is overwritten on the first tape in the present backup system will be described. In this case, the system first releases the first recorded 30 GB data (the first data and the T end signal) as shown in FIG. At the same time as overwriting the data, the fact that the addresses 4, 5,... N + 1 are empty is set in the area management table 221 as shown in FIG.
[0026]
At this time, if the first overwrite data is larger than the capacity initially stored, the system writes data to the opened storage area as shown in FIG. Following the T end signal of the third tape described in (e), data writing and setting of the T end signal are performed.
If the first overwrite data is smaller than the capacity initially stored, the system writes data and sets a T termination signal in the open storage area as shown in FIG. 2 (g).
[0027]
At this time, a tape number such as a first / second / third tape and a T end signal are set in the area management table 221 for each address, and the controller 21 of the control device 20 monitors the area management table 221. Thus, data in the virtual tape storage device can be managed.
[0028]
In the virtual tape backup system according to the present embodiment, as described above, the area management / control unit 22 of the backup control device 20 stores an index for each tape in the area management table 221 and stores data for each volume as viewed from the system side. When writing data and setting the T-terminus signal for each winding, data backup corresponding to one virtual tape is performed. When this operation is viewed from the system side, data backup is performed for each winding, and further data overwriting is performed. Also, an area in which the corresponding data and the T-terminal signal are already recorded is released, and an extra empty area is overwritten by overwriting data (an empty area when the capacity increases) and the T-terminal signal in this open area. This does not occur, and abnormal termination due to erroneous detection of the T terminal signal can be prevented.
[0029]
That is, in this embodiment, when overwriting one piece of virtual tape data, after releasing the data previously stored in the virtual magnetic tape storage device and the T end signal, the overwritten data is written to the released free storage area. Write, write a T end signal at the end of the overwrite data, rewrite the tape information stored in the area management table corresponding to the address where the overwrite data and the T end signal are stored, and close as one virtual tape for each backup This makes it possible to detect the end of the virtual magnetic tape and prevent the state of waiting for insertion of the next magnetic tape or abnormal termination.
[0030]
In the above embodiment, as shown in FIG. 2G, one sequential virtual tape data is divided by overwriting data, and one virtual tape data is further divided and subdivided by repeating further overwriting. It is possible. In this system, when one piece of virtual tape data is subdivided in this way, in order to eliminate the subdivision during the idle time of the system or the like, the data is set so that the one piece of virtual tape data is continuous on the storage area. (Defragmentation) may be performed.
[0031]
The present invention includes, for example, a virtual magnetic tape storage device that stores backup data, and a backup control device that controls backup of the virtual magnetic tape storage device. One backup is defined as one tape with a tape number set. In the virtual tape backup system to be controlled, the backup control device is configured to control an address of a storage area of the virtual magnetic tape storage device and, in correspondence with the address, an index or a tape number for each tape number or a T-termination signal or an empty area for each tape number And an area management table for storing tape information composed of a plurality of tape numbers. In data backup, an index for a plurality of tape numbers is stored, and then data for each tape number and a T end signal are sequentially stored. You can also.
[0032]
【The invention's effect】
As described above, the present invention provides a virtual tape backup system in which one backup is controlled as one virtual tape with a tape number set therein. An area management table for storing an index for each number, a tape number, a T-end signal for each tape number, or a tape information comprising an empty area is provided, and at the time of data backup, the tape information corresponding to the address stored in the area management table is referred to. Thus, by making the data capacity of each virtual tape variable, the entire capacity of the magnetic disk can be used efficiently.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram for explaining the overall configuration of a backup system according to an embodiment of the present invention.
FIG. 2 is an exemplary view for explaining a data storage procedure according to the embodiment;
FIG. 3 is an exemplary view for explaining an area management table according to the embodiment;
FIG. 4 is a diagram for explaining generation of a free area according to the related art.
FIG. 5 is a diagram for explaining a data backup procedure for a plurality of generations according to the related art.
[Explanation of symbols]
10: backup server, 20: backup control device, 30: virtual tape storage device, 21: controller, 22: area management / control unit, 23: interface control unit, 221: area management table.

Claims (3)

A virtual tape backup system that includes a virtual magnetic tape storage device that stores backup data and a backup control device that controls backup of the virtual magnetic tape storage device, and controls one backup as one virtual tape with a tape number set. At
An area in which the backup control device stores an address of a storage area of the virtual magnetic tape storage device and, corresponding to the address, an index for each tape number or a tape number or a tape termination signal for each tape number or a tape information including a free area. A virtual tape backup system comprising a management table, wherein at the time of data backup, the data capacity of each virtual tape is made variable by referring to tape information corresponding to an address stored in the area management table. When overwriting one virtual tape data, after releasing the data previously stored in the virtual magnetic tape storage device and the T end signal, the overwrite data is written into the released empty storage area, and the end of the overwritten data is written. 2. The virtual tape backup system according to claim 1, wherein a T end signal is written, and the tape information stored in the area management table is rewritten corresponding to the address where the overwrite data and the T end signal are stored. When one piece of virtual tape data is subdivided on the storage area by writing the overwrite data, the data is rearranged so that the one piece of virtual tape data is continuous on the storage area. The virtual tape backup system according to claim 2.

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