JP2007323589A - Copy control method, copy controller, and copy control program for virtual volume - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an allocation method of physical storage areas to virtual volumes in a hierarchical virtual storage device using a hard disk device and a tape library device. <P>SOLUTION: In the hierarchical virtual storage, physical data copying on a tape is not carried out but only management information of the virtual volume is copied to create another virtual volume. When a reading request is made, the virtual volume is made to be acquired as necessary data. When update/new writing is carried out, a new physical storage area is allocated to each virtual volume. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a physical storage area allocation technique for copying a virtual volume at high speed in a hierarchical virtual storage system using a hard disk device and a tape library device.

  In recent years, a hierarchical storage system that uses a plurality of storage devices in combination and secures a substantially large storage area is generally provided. This is because high-speed but small-capacity storage is used as primary storage, and in the following order, storage that is slower but larger is secondary storage, tertiary storage, and so on. It is a system that shows virtually as one storage. Therefore, low-cost, large-capacity, high-performance storage is realized by placing frequently accessed data on the primary storage side and placing less frequently accessed data below the secondary storage. (For example, refer to Patent Document 1).

  In such a large-scale storage system, the information stored in the storage changes over time, so it is necessary to store it efficiently and safely over a long period of time, and the increase in storage management costs, including maintenance costs, can be suppressed. Information lifecycle management is becoming important. For this reason, for example, frequently used information is managed by high-speed online storage such as a large-capacity hard disk that can be accessed in a short time, and low-cost offline information such as magnetic tape is used for information that is infrequently used but requires long-term storage. Measures such as management by storage are taken.

However, when a hierarchical virtual storage system based on information lifecycle management is composed of a hard disk device and a tape library device, the tape library device drives out less frequently accessed data from the disk. It is positioned as a “low-speed but inexpensive storage area” to be stored for a long time. In such a tiered storage system, in order to back up the entire virtual volume, a large amount of tape-to-tape copying occurs, which exposes poor response performance to a storage system composed only of disk devices. Therefore, when backing up data, it is necessary to suppress the occurrence of low-speed tape-to-tape copying.
JP 2002-215334 A

  In order to solve the above problem, in the present invention, in a hierarchical virtual storage composed of a hard disk device and a tape library device, a large-capacity virtual volume appears to be logically copied at high speed. Thus, a technique is provided in which only virtual volume management information is copied to create another virtual volume without making any data copy, and the user can see a large-capacity storage area as if it was copied at high speed.

  The virtual volume created by copying points to the storage area that is physically the same as the copy source virtual volume for the existing data, so that necessary data can be acquired at the time of a read request. In addition, when performing update / new writing to a virtual volume, a new physical storage area is allocated for each virtual volume. By this method, a new virtual storage area is provided to the user with the existing data already copied.

  A first invention is a virtual volume copy control method in a hierarchical virtual storage system composed of a hard disk device and a tape library device. The virtual volume and the tape library device are physically controlled in response to a copy request from a user. Checking the existence of actual data in the physical storage area by referring to the management table associated with the physical storage area, and only management information of the management table when actual data exists in the physical storage area And copying the same physical storage area to the copy source / destination virtual volume, and a virtual volume copy control method.

  That is, according to the first invention, in response to a copy request from the user, the management information storing the management information in which the virtual volume and the physical storage area of the tape library device are associated is referred to, and the management information is checked. If the requested data is already written in the tape library device, the virtual volume of the copy source / destination can be allocated to the same physical area by copying only the management information in the management table. High speed copy can be realized.

  As described above, according to the present invention, a virtual volume can be copied at high speed in a hierarchical virtual storage. In addition, when multiple copies are created from a single virtual volume, each copied virtual volume shares existing data as a physical storage area, so only a difference is required for the new physical storage area. Efficient operation of low-speed storage such as devices can be achieved.

  According to a second aspect of the present invention, when a data change occurs in the virtual volume, the actual data on the hard disk device corresponding to the virtual volume is updated at the copy source, and the updated actual data is associated with the virtual volume. A virtual volume of the virtual volume according to the first aspect of the present invention, further comprising: a step of additionally writing to the physical storage area of the tape library device, and a step of rewriting position information on the tape of the actual data that has been additionally written. The present invention relates to a copy control method.

  The third invention reads the update target data from the tape library device to the hard disk device at the copy destination when the data change occurs in the virtual volume, updates the data on the hard disk device, and updates the data. The virtual data according to the first aspect, wherein real data is added to the physical storage area of the tape library device corresponding to the virtual volume, and location information on the tape of the added real data is rewritten. The present invention relates to a volume copy control method.

  That is, according to the second or third invention, when the data change is necessary for the virtual volume, the target data has already been written on the tape, so the copy source or the copy destination supports the target virtual volume. By updating the actual data on the hard disk device, writing the updated data to a new physical storage area of the tape library device, and replacing the management information such as position information on the tape corresponding to the target virtual volume, The complexity of the update work is reduced. In addition, since the tape is a write-once type storage medium, it is possible to improve the efficiency of the update work that has taken a long time by simply deleting the position information on the tape from the virtual volume that is no longer needed.

As described above, the following effects are produced by the above-described invention.
(1) In a hierarchical virtual storage system, in response to a copy request from a user, a management table storing management information in which a virtual volume and a physical storage area of a tape library device are associated is referred to and the management information is checked. If the requested data is already written in the tape library device, the virtual volume of the copy source / destination can be allocated to the same physical area by copying only the management information in the management table. High speed copy can be realized. In addition, when a plurality of copies are created from one virtual volume, the copied virtual volumes share existing data as physical storage areas, so that the new physical storage area needs only a difference.

That is, in a tiered virtual storage, a large-capacity virtual volume can be copied at high speed without data transfer between tapes, and the time required to stop the operation at the time of volume backup can be shortened.
(2) Also, if there is a data change in the virtual volume, the target data has already been written to the tape, so the changed data is written to a new physical storage area, and management of positional information on the tape corresponding to the virtual volume, etc. Just change the information. Further, since the tape is a write-once type storage medium, it is possible to cope by simply deleting the position information on the tape from the virtual volume that is no longer needed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a basic configuration of a virtual volume copy control system in a hierarchical virtual storage system according to an embodiment of the present invention.

  The hierarchical virtual storage system is interposed between the hard disk device 101, the primary storage, and the secondary storage 200 as the primary storage 100 connected to the host 0, receives requests from the host 0, and manages the exchange with the secondary storage 200 The management server 1 and the secondary storage 200 are composed of a tape library device 201 containing a plurality of tapes 1, 2,... N. The management server 1 is a computer including a CPU (Central Processing Unit) 2 and a memory 3, and includes a copy control unit 10 for executing a virtual volume copy and a management table 20.

  Here, a data processing operation between devices in the hierarchical virtual storage will be described. The primary storage 100 incorporates a primary storage control program 102 as firmware for primary storage control, and is configured to issue a read / write request to the management server 1 that manages the secondary storage 200.

  The primary storage control program 102 performs the following processing so that the host 0 can show a large virtual volume larger than the capacity of the hard disk device 101 as the primary storage 100 and can be used as a normal disk.

  When a data write request is received from the host 0, if the capacity of the hard disk is likely to be exceeded, the management server 1 is instructed to write old data to the secondary storage 200. When the writing to the secondary storage 200 is completed, the old data is deleted from the primary storage to create a free space. Further, when a data read request is received from the host 0, if the data exists in the hard disk device 101, the data is returned to the host 0 as it is. If it is not on the hard disk device 101, it makes a data read request to the management server 1, collects data from the secondary storage 200, and returns it to the host 0.

  Further, when the primary storage control program 102 requests the management server 1 to read / write data, it designates the virtual volume number, so the management server 1 is a virtual volume, tape, and real data. A management table 20 (consisting of a virtual volume management TBL (table) 21, a tape management TBL 22, and a data block TBL 23) in which data blocks are associated with each other is searched to determine a data position on the tape, and a read / write request is made. Will answer.

  On the other hand, in the management server 1, the virtual volume copy control unit 10 refers to the management information in the management table 20 in which the virtual volume and the physical storage area of the tape library apparatus 101 are associated with each other in response to a copy request from the user. Then, the existence of the actual data in the physical storage area is checked, and when the actual data exists, only the management information in the management table 20 is copied and the same physical storage area is allocated to the copy source / copy destination virtual volume.

  Further, when updating the write data of the virtual volume, the actual data (or data block) of the hard disk device 101 is updated at the copy source or copy destination of the virtual volume, and the update data is stored on the tape of the tape library device 201. It is configured to perform additional writing.

  FIG. 2 shows a data configuration example of a management table for managing virtual volumes according to the embodiment of the present invention. Among the management tables 20, (a) shows a virtual volume management table 21, (b) shows a tape management table 22, and (c) shows a data configuration example of the data block management table 23.

  The virtual volume management table 21 includes the “identifier” of the virtual volume uniquely identified in the system, the “volume number”, “volume name”, “capacity”, “creation date / time” of the virtual volume, and the virtual volume related to errors and usage. It consists of items of “status” representing state information and “permission” representing read / write access permission to the virtual volume.

  The tape management table 22 indicates the correspondence relationship between the “identifier”, “label name”, “tape type” of the tape, “tape type” indicating the tape mount form, and the virtual volume in the virtual volume management table 21. It consists of an item of “Affiliated Volume ID” that becomes a pointer.

  Further, the data block management table 23 includes an “identifier” of the data block, an “affiliation volume ID” and “affiliation tape ID” that are pointers to the virtual volume and the tape, an “address on the volume” in the hard disk, and an “on tape”. It includes items of “position”, “data size”, and “reference counter” indicating the number of referenced virtual volumes.

  FIG. 3 is a conceptual diagram of virtual volume copy when the same data according to the embodiment of the present invention exists on a tape. In this embodiment, a virtual volume in which all data on the hard disk device 101 is written on a plurality of tapes in the tape library device 201 is targeted.

  In the present invention, only virtual volume management information is copied to create a new virtual volume, and all existing data at the time of copying is pointed to the same physical storage area in the copy source / copy destination virtual volume. In the figure, it is conceptually shown that a certain data block as actual data of the target virtual volume on the hard disk is held in the same physical storage area on the tape. Show.

  FIG. 4 is a conceptual diagram when data is updated in the copy source virtual volume according to the embodiment of the present invention. The present embodiment conceptually shows a procedure for performing an update at the copy source when the data needs to be updated in the virtual volume.

  At the copy source, first, the data block on the hard disk corresponding to the target virtual volume is updated, and then the updated data block is added to the tape of the tape library apparatus 201 corresponding to the target virtual volume, and The position information on the tape of the added data block is rewritten.

  Here, immediately after the virtual volume is copied, all the data blocks are referenced from the two virtual volumes of the copy destination and the copy source. Therefore, the value of the reference counter in the data block management table 23 of FIG. It has become. When data is updated and only one virtual volume is referred to, the reference counter of the data block in that case becomes 1.

  Since the tape is a write-once storage medium, when this data is updated and an updated data block is additionally written, the reference counter of the original data block becomes 0. Since the data block whose reference counter is 0 is not allocated to any virtual volume, it becomes simply invalid data and becomes a deletion target in garbage collection for performing unnecessary data deletion processing.

  FIG. 5 shows a conceptual diagram when data is updated in the copy destination virtual volume according to the embodiment of the present invention. The present embodiment conceptually shows a procedure for performing an update at the copy destination when the data needs to be updated in the virtual volume.

  At the copy destination, the data block to be updated is read from the tape of the tape library apparatus 201 to the hard disk, the data block is updated on the hard disk, and the updated data block is physically stored in the tape library apparatus 201 corresponding to the target virtual volume. Information is added to the target storage area and the position information on the tape of the added data block is rewritten.

  FIG. 6 shows a processing flow of virtual volume copy when the same data according to the embodiment of the present invention exists on the tape according to the embodiment of the present invention. 4 shows a processing flow of backup copy of a virtual volume in the hierarchical virtual storage system shown in the conceptual diagram of FIG. In this embodiment, it is assumed that there is a virtual volume serving as a copy source, and data blocks on the volume are written to tape.

  In step S11, the virtual volume is created by copying the configuration information of the copy source virtual volume. In step S12, the configuration information is updated so that the copy destination virtual volume points to the same data block as the copy source.

  As described above, in the present invention, a backup of a virtual volume is newly created by copying only the configuration information of the management table 20, and the copy source / copy destination virtual volume is completely as data in the physical storage area on the tape. The same data block can be used.

  FIG. 7 shows a processing flow of data update of the virtual volume at the copy source according to the embodiment of the present invention. The present embodiment is a processing flow for updating virtual volume data in the hierarchical virtual storage system shown in the conceptual diagram of FIG. 4, in which a copy of the virtual volume is created by copying the configuration information, and the copy source and destination virtual The data update at the copy source when the volume points to the same data in the physical storage area is shown.

  First, in step S21, a certain data block is updated in the copy source virtual volume. Next, in step S22, the data block on the hard disk corresponding to the virtual volume is updated, and in step S23, the changed data block is added to the tape corresponding to the virtual volume. In step S24, the position information of the tape management table 22 is changed so as to indicate the data block added to the data on the tape corresponding to the virtual volume.

  As described above, an updated data block refers to a data block in a physical storage area with different copy source / copy destination virtual volumes.

  FIG. 8 shows a processing flow of data update of the virtual volume at the copy destination according to the embodiment of the present invention. This embodiment is a processing flow for updating data of a virtual volume in the hierarchical virtual storage system shown in the conceptual diagram of FIG. 5, and data at the copy destination when a copy of the virtual volume is created by copying configuration information Indicates an update.

  First, in step S31, a certain data block is updated in the copy destination virtual volume. Next, in step S32, a disk area is allocated to the virtual volume and data is written, and in step S33, the changed data block is added to the tape corresponding to the virtual volume. In step S34, the position information of the tape management table 22 is changed so as to indicate the data block added to the data on the tape corresponding to the virtual volume.

  As described above, the data change process at the copy destination of the virtual volume adds the updated data block to the tape, and the position information in the tape management table 22 is updated so that the virtual volume points to the data. Become.

It is a figure which shows one basic composition of the copy control system of the virtual volume in the hierarchical virtual storage system which becomes embodiment of this invention. It is a figure which shows the example of a data structure of the management table which manages the virtual volume which becomes embodiment of this invention. It is a conceptual diagram of a virtual volume copy when the same data according to an embodiment of the present invention exists on a tape. It is a conceptual diagram in the case of updating data in the copy source virtual volume according to the embodiment of the present invention. It is a conceptual diagram in the case of updating data in the copy destination virtual volume according to the embodiment of the present invention. It is a figure which shows the processing flow of a virtual volume copy in case the same data which become embodiment of this invention exists on a tape. It is a figure which shows the processing flow of the data update of the virtual volume in the copy source which becomes embodiment of this invention. It is a figure which shows the processing flow of the data update of the virtual volume in the copy destination which becomes embodiment of this invention.

Explanation of symbols

0 Host 1 Management server 2 CPU
3 Memory 10 Virtual Volume Copy Control Unit 20 Management Table 21 Virtual Volume Management Table 22 Tape Management Table 23 Data Block Management Table 100 Primary Storage 101 Hard Disk Device 102 Primary Storage Control Program 200 Secondary Storage 201 Tape Library Device

Claims (5)

A virtual volume copy control method in a hierarchical virtual storage system composed of a hard disk device and a tape library device,
In response to a copy request from a user, referring to a management table in which the virtual volume and the physical storage area of the tape library device are associated with each other, and checking the presence of actual data in the physical storage area;
Copying only the management information of the management table when real data exists in the physical storage area, and allocating the same physical storage area to the copy source / copy destination virtual volume;
A copy control method for a virtual volume, comprising:   When data change occurs in the virtual volume, the actual data on the hard disk device corresponding to the virtual volume is updated at the copy source, and the updated real data is updated in the tape library device corresponding to the virtual volume. The virtual volume copy control method according to claim 1, further comprising a step of additionally writing to a physical storage area, and a step of rewriting position information on the tape of the added actual data.   When data change occurs in the virtual volume, the update target data is read from the tape library device to the hard disk device at the copy destination, the data is updated on the hard disk device, and the updated actual data corresponds to the virtual volume. The virtual volume copy control method according to claim 1, further comprising: rewriting the physical data in the physical storage area of the tape library device to be rewritten, and rewriting the position information on the tape of the real data that has been additionally written. A virtual volume copy control device in a hierarchical virtual storage system composed of a hard disk device and a tape library device,
Means for checking the presence of actual data in the physical storage area by referring to a management table in which the virtual volume and the physical storage area of the tape library device are associated in response to a copy request from a user;
Means for copying only the management information of the management table and allocating the same physical storage area to a copy source / copy destination virtual volume when actual data exists in the physical storage area;
A virtual volume copy control apparatus comprising: A virtual volume copy control program in a hierarchical virtual storage system composed of a hard disk device and a tape library device,
On the management server,
In response to a copy request from a user, referring to a management table in which the virtual volume and the physical storage area of the tape library device are associated with each other, and checking the presence of actual data in the physical storage area;
Copying only the management information of the management table when real data exists in the physical storage area, and allocating the same physical storage area to the copy source / copy destination virtual volume;
Virtual volume copy control program to execute.

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