JP2013012137A - Disk mirroring system and its management method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a disk mirroring system capable of managing an optional number of mirror disks without requiring a large management area for difference information, and its management method.SOLUTION: A main site device gives each mirroring process a mirroring process number which is a number to be updated in each mirroring process. When a difference is generated due to a writing failure in any of sub-site devices in a mirroring process, the main site device creates difference information indicating the difference, including a mirroring process number corresponding to the mirroring process, and stores it in association with data. Each of the sub-site device updates the mirroring process number when a mirroring process is generated, while it determines whether there is data to be restored in a restoration process, on the basis of the difference information transmitted from the main site device and when there is data to be restored, the sub-site device requests the main site device to transmit the data to it.

Description

  The present invention relates to a disk mirroring system for recording and storing the same contents in a plurality of storage devices, and a management method thereof.

  As a countermeasure against hard disk drive failures, a disk mirroring method is known in which the same contents are recorded and stored in a plurality of hard disk drives. In recent years, various nodes equipped with storage devices can be connected via a LAN (Local Area Network), the Internet, etc. due to the progress of network technology, and the location of the storage device to be mirrored can be freely set. You can choose.

  The disk mirroring method is also described in Patent Documents 1-4.

Japanese Patent Laying-Open No. 2005-078153 JP 2006-323663 A Japanese Patent Laid-Open No. 2008-140086 JP 2009-110303 A

  In the disk mirroring system, the data stored on each disk can be copied by changing the contents of the original storage device (hereinafter simply referred to as “disk”), or by copying only the differences periodically or as necessary. It is necessary to maintain identity.

  As a difference management method in such a disk mirroring system, there is a method previously proposed by the present applicant (for example, see Japanese Patent Application No. 2010-127517). In this difference management method, a one-to-one disk mirroring method of copying (mirroring) information stored on one original disk to another disk is applied to mirroring on a plurality of disks, respectively. A one-to-many disk mirroring system is realized.

  However, in such a disk mirroring system, since it is necessary to manage the difference information indicating the difference from the original for each disk to be mirrored, there is a problem that the amount of difference information increases as the number of disks to be mirrored increases. .

  The difference information is normally managed by an information processing device (computer). However, since the storage capacity of the information processing device is limited, the number of disks that can be mirrored is limited when the amount of difference information increases.

  The present invention has been made to solve the problems of the background art as described above, and a disk mirroring system capable of managing an arbitrary number of mirror disks without providing a large difference information management area and its management It aims to provide a method.

In order to achieve the above object, a disk mirroring system of the present invention includes a main site device including an original storage device,
A sub-site device group comprising at least one sub-site device comprising a storage device for storing a copy of the data stored in the storage device of the main site device;
A disk mirroring system comprising:
The main site device is
A mirroring processing device for assigning a mirroring processing number, which is a number updated for each mirroring processing, to a mirroring processing for storing a copy of the data in the secondary site device;
When a difference occurs due to failure in writing the copy of the data in any of the secondary site devices during the mirroring process, differential information indicating the difference including a mirroring process number corresponding to the mirroring process is generated, and A difference management device that stores the data in association with the data;
Have
The secondary site device is
A mirroring processing device that saves data transmitted from the main site device in the storage device and updates a mirroring processing number corresponding to the mirroring processing when the mirroring processing occurs,
At the time of recovery processing for matching the contents of the storage device of the secondary site device with the storage device of the main site device, the presence / absence of data to be recovered is determined based on the difference information transmitted from the main site device, and the recovery A difference management device that requests the main site device to transmit the data if there is data to be transmitted;
Have

On the other hand, the management method of the disk mirroring system of the present invention includes a main site device including an original storage device,
A sub-site device group comprising at least one sub-site device comprising a storage device for storing a copy of the data stored in the storage device of the main site device;
A disk mirroring system management method comprising:
The main site device is
A mirroring process number that is a number updated for each mirroring process is assigned to a mirroring process that stores a copy of the data in the secondary site device, respectively.
When a difference occurs due to failure in writing the copy of the data in any of the secondary site devices during the mirroring process, differential information indicating the difference including a mirroring process number corresponding to the mirroring process is generated, and Save it in association with the data,
The secondary site device is
The data transmitted from the main site device is stored in the storage device, and when the mirroring process occurs, the mirroring process number corresponding to the mirroring process is updated,
At the time of recovery processing for matching the contents of the storage device of the secondary site device with the storage device of the main site device, the presence / absence of data to be recovered is determined based on the difference information transmitted from the main site device, and the recovery This is a method of requesting the main site device to transmit the data when there is data to be transmitted.

  According to the present invention, an arbitrary number of mirror disks can be managed without providing a large difference information management area.

It is a block diagram which shows the example of 1 structure of the disk mirroring system of this invention. It is a schematic diagram which shows the relationship between the difference information used by this invention, and a mirroring process number. It is a flowchart which shows an example of the process sequence of the main site apparatus in a mirroring process. It is a schematic diagram which shows an example of the update process of the difference information in the main site apparatus shown in FIG. It is a flowchart which shows an example of the process sequence of the secondary site apparatus in a mirroring process. It is a schematic diagram which shows an example of the update process of the difference information in the secondary site apparatus shown in FIG. It is a flowchart which shows an example of the process sequence of the main site apparatus at the time of a recovery process. It is a flowchart which shows an example of the process sequence of the sub site apparatus at the time of a recovery process. It is a schematic diagram which shows an example of the procedure of the update process of the mirroring process number at the time of the recovery of the secondary site apparatus shown in FIG.

  Next, the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration example of the disk mirroring system of the present invention.

  As shown in FIG. 1, the disk mirroring system of the present embodiment stores a main site apparatus 1 having an original storage device (disk) and a copy of data stored on the disk of the main site apparatus 1 (mirroring). ) Having a secondary site device group 2 having storage devices (disks) and a host device H that stores data in the main site device 1 or reads and uses data from the main site device 1. In this configuration, the device 1 and the secondary site device group 2 are connected via a network N.

  The main site device 1 includes an I / O control device 101, a mirroring processing device 102, a difference management device 103, a disk 104, a mirroring processing number holding device 105, and a difference information holding device 106.

  The I / O control device 101 executes data writing to the disk 104 and data reading from the disk 104 in accordance with instructions from the host device H.

  When the host device H requests to write data to the disk 104, the mirroring processing device 102 executes mirroring processing for storing a copy of the data in each secondary site device 20 of the secondary site device group 2. Further, when the mirroring process occurs, the mirroring processing apparatus 102 updates the mirroring process number for identifying the mirroring process stored in the mirroring process number holding apparatus 105 (A2 in FIG. 2).

  The difference management device 13 generates difference information indicating the difference and stores it in the difference information holding device 106 when mirroring fails in any of the secondary site devices 20 during mirroring processing and a difference occurs. The difference information is stored in the difference information holding device 106 in association with the data at the time of occurrence of the difference stored for each required section in the disk 104 (A1 in FIG. 2). The difference information includes a mirroring process number corresponding to the mirroring process in which the difference has occurred. As described above, since the mirroring process number is updated every time the mirroring process is executed, the primary site apparatus 1 and the secondary site apparatus 20 can specify the time-series order of the generated differences based on the mirroring process number. If a difference occurs a plurality of times when data is written a plurality of times to the same area (section) of the storage device, the difference information generated last is held.

  As shown in FIG. 1, the secondary site device group 2 includes at least one secondary site device 20. The secondary site device 20 includes an I / O control device 201, a mirroring processing device 202, a difference management device 203, a disk 204, a mirroring processing number holding device 205, and a difference information holding device 206.

  The I / O control device 201 executes data writing to the disk 204 and data reading from the disk 204 in accordance with instructions from the main site device 1.

  When the main site device 1 requests data writing (mirroring), the mirroring processing device 202 writes the data to the disk 204 via the I / O control device 201. Further, when the mirroring process occurs, the mirroring processing apparatus 202 updates the mirroring process number corresponding to the mirroring process stored in the mirroring process number holding apparatus 205.

  The difference management device 203 manages difference information corresponding to data in the disk 204 of the secondary site device 20. The difference management device 203 should recover based on the difference information transmitted from the main site device 1 during the recovery process in which the content of the disk 204 of the secondary site device 20 in which the difference has occurred coincides with the disk 104 of the main site device 1. The presence / absence of data (hereinafter also referred to as difference data) is determined. If there is difference data to be recovered, the main site apparatus 1 is requested to transmit the difference data via the mirroring processing apparatus 202.

  The host device H, the main site device 1 and the sub site device 20 shown in FIG. 1 can be realized by an information processing device including a known CPU (Central Processing Unit), DSP (Digital Signal Processor), storage device and the like. In this case, the CPU implements functions as the host device H, the main site device 1, and the sub site device 20 by executing processing in accordance with a predetermined control program stored in the storage device.

  Next, the operation of the disk mirroring system of this embodiment will be described with reference to the drawings.

  The primary site device 1 and the secondary site device 20 provided in the disk mirroring system of the present embodiment include a mirroring process that saves a copy of the data saved on the disk 104 of the primary site device 1 on the disk 204 provided in each secondary site device 20. Then, a recovery process is executed to match the contents of the disk 204 of the secondary site apparatus 20 in which the difference has occurred with the disk 104 of the primary site apparatus 1.

  First, the operation of the main site apparatus 1 in the mirroring process will be described with reference to FIGS.

  The mirroring process in the main site device 1 is started when an I / O request is issued from the host device H to the main site device 1.

  As shown in FIG. 3, the main site device 1 waits for an I / O request from the host device H (step B10), and when an I / O request is issued from the host device H, the I / O control device 101 The type of the I / O request is determined (step B11).

  When the I / O request is data reading, the I / O control device 101 reads the designated data from the disk 104 (step B30) and transmits the read data to the host device H (step B13).

  When the I / O request is a write, the I / O control device 101 writes the data transmitted from the host device H to the disk 104 (step B12), and the mirroring processing device 102 performs the mirroring process for the secondary site device group 2. After completion, the host device H is notified of the result of writing to the disk 104 (step B13).

  When the mirroring processing occurs, the mirroring processing device 102 updates the mirroring processing number stored in the mirroring processing number holding device 105 (step B20), and all the secondary site devices in the secondary site device group 2 via the network N. A data write request is transmitted to 20 (step B21).

  Subsequently, the mirroring processing device 102 transmits data to be written (data written to the disk 104 in accordance with an instruction from the host device H) to each secondary site device 20 (step B22), and writing from each secondary site device 20 is performed. The result is awaited (step B23).

  The mirroring processing device 102 confirms the writing result transmitted from each secondary site device 20 (step B24), and when the success of writing is notified from all the secondary site devices 20, the mirroring processing ends.

  On the other hand, when writing fails in any of the secondary site devices 20, the mirroring processing device 102 updates the difference information stored in the difference information holding device 106 by the difference management device 103 (step B25), and then performs mirroring processing. Exit. The difference information update process in the main site apparatus 1 will be described with reference to FIG.

  When the mirroring processing device 102 is notified of data write failure from any of the secondary site devices 20 in the secondary site device group 2 (C1 in FIG. 4), the difference corresponding to the data that failed to write (difference data) The difference management device 103 searches the difference information stored in the information holding device 106 (C2 in FIG. 4), and writes the mirroring process number at that time in the difference information (C3 in FIG. 4).

  Next, the operation of the secondary site apparatus 20 in the mirroring process will be described with reference to FIGS.

  As shown in FIG. 5, the secondary site device 20 waits for a data write request from the main site device 1 (step D10), and receives the data to be written (step D11). The operation state of the own site is determined (step D12).

  When the local site is undergoing recovery processing, the secondary site device 20 does not write the received data to the disk 204 even when data writing is requested from the primary site device 1 (E1 in FIG. 6), and only updates the difference information. Do. Specifically, the difference information corresponding to the data received by the difference management device 203 is updated (step D20), and the data writing failure is notified to the main site device 1 that has requested writing by the mirroring processing device 202 (step D21). ).

  When updating the difference information, as shown in FIG. 6, the difference management device 203 searches the difference information stored in the difference information holding device 206 for the latest difference information and confirms the mirroring process number ( E2 in FIG. 6). Further, the difference information that needs to be updated corresponding to the data that needs to be restored (difference data) is searched (E3 in FIG. 6), and the mirroring process number is updated so that the difference information becomes the latest (in FIG. 6). E4).

  In step D12 of FIG. 5, when the secondary site apparatus 20 is operating normally, the mirroring processing apparatus 202 writes the data received by the I / O control apparatus 201 to the disk 204 (step D13), and subsequently It is determined whether or not the writing is successful (step D14).

  When the data writing to the disk 204 is successful, the mirroring processing device 202 updates the mirroring processing number stored in the mirroring processing number holding device 205 (step D15), and sends data to the main site device 1 that has requested the data writing. Is notified of the writing success (step D16).

  On the other hand, when the data writing to the disk 204 fails, or when the secondary site device 20 is in the recovery process and the difference information is updated, the main site device 1 is notified of the data writing failure (step D21).

  Note that the data that failed to be written because the secondary site device 20 is in the recovery process has the corresponding difference information updated, so the data is finally written by the recovery process being executed in the secondary site device 20. The

  Therefore, when the recovery process being executed in the secondary site apparatus 20 is completed, there is no difference data between the disk 104 of the primary site apparatus 1 and the disk 204 of the secondary site apparatus 20, so the recovery process is executed again. There is nothing to do.

  Next, the operation of the main site device 1 during the restoration process will be described with reference to FIG.

  As shown in FIG. 7, when the primary site 1 detects the addition of the secondary site device 20 by resuming the operation of the secondary site device 20 that has been stopped due to a failure or the like (step F10), mirroring is performed regardless of the difference. The processing device 102 requests the secondary site device 20 to restore mirroring (step F11), and transmits the difference information obtained from the difference management device 103 and corresponding to the data that failed to be written to the secondary site device 20. (Step F12), waiting for a response from the secondary site device 20 (Step F13).

  When receiving a response from the secondary site device 20, the mirroring processing device 102 confirms the content of the response (step F14), and when the recovery completion is notified from the secondary site device 20, the recovery processing is terminated.

  On the other hand, when the differential data is requested from the secondary site device 20, the requested differential data is acquired from the disk 104 via the I / O control device 101 (step F20) and sent to the requesting secondary site device 20. The difference data is transmitted (step F21). Thereafter, returning to the process of step F13, the processes of steps F13 and F14 and steps F20 and F21 are repeated until the completion of restoration is notified from the secondary site apparatus 20.

  Next, the operation of the secondary site device 20 during the recovery process will be described with reference to FIG.

  As shown in FIG. 8, when the secondary site device 20 receives a mirroring recovery request from the primary site device 1, the secondary site device 20 starts recovery processing (step G10).

  When receiving the difference information from the main site device 1 (step G11), the secondary site device 20 determines the difference data necessary for the restoration of its own site by the difference management device 203 based on the received difference information (step G12).

  Next, the difference management device 203 determines whether or not there is difference data necessary for the recovery of its own site (step G13). (Step G14), and the recovery process is terminated.

  On the other hand, if there is difference data, the difference synchronization processing shown in steps G20 to G24 is repeated until there is no difference data. At this time, the presence / absence of difference data is determined in order from the oldest mirroring process according to the mirroring process number included in the difference information.

  In the difference synchronization processing, the difference management device 203 first requests the main site device 1 to transmit difference data corresponding to the difference information via the mirroring processing device 202 (step G20).

  When receiving the difference data from the main site device 1 (step G21), the I / O control device 201 writes the difference data to the disk 204 (step G22). Subsequently, the mirroring processing number stored in the mirroring processing number holding device 205 is updated by the mirroring processing device 202 (step G23). Thereafter, the process returns to step G13 and the processes of step G13 and steps G20 to G23 are repeated until there is no difference data to be restored.

  The update process of the mirroring process number of the secondary site apparatus 20 during the recovery process will be described with reference to FIG.

  As shown in FIG. 9, the secondary site device 20 stores the difference information corresponding to the data written by the difference management device 203 in the difference information holding device 206 (H1 in FIG. 9). Based on the value of the mirroring processing number included in the difference information, the mirroring processing number stored in the mirroring processing number holding device 205 is overwritten and updated by the mirroring processing device 202 (H2 in FIG. 9).

  According to the disk mirroring system of the present embodiment, a number is assigned to each mirroring process, and the difference information including the mirroring process number is stored in association with the data in the disk 104 of the primary site device 1, so that the secondary site The device 20 can determine the presence / absence of difference data necessary for recovery of the own site based on the difference information received from the main site device. Therefore, the secondary site device 20 can acquire the difference data necessary for recovery by requesting the main site device 1, and can match the contents of the disk 204 with the disk 104 of the main site device 1. .

  Therefore, the main site device 1 does not need to manage the difference information for each secondary site device 20, and only stores the difference information including the mirroring process number corresponding to the occurrence of the difference. Therefore, the main site apparatus 1 can manage an arbitrary number of mirror disks without providing a large difference information management area.

  Further, even if the number of secondary site devices 20 to be mirrored increases or decreases, it is not necessary to change the difference information, so that the secondary site device 20 to be mirrored can be easily added or deleted.

  In the above description, the configuration example in which the primary site device 1 and the secondary site device 20 each include a disk, a mirroring processing number holding device, and a difference information holding device has been described. However, the disk, the mirroring processing number holding device, and the difference information holding The device can also be realized by a single storage device. In that case, one storage device may be divided into three areas, and these three areas may be used as a disk, a mirroring process number holding device, and a difference information holding device.

  Furthermore, in the above description, an example is shown in which one difference information is associated with one data and stored, but one difference information may be associated with and stored with an arbitrary number of continuous data. In that case, difference information associated with a plurality of data, difference information associated with one data, and the like may be mixed.

  When there is difference information associated with a plurality of data, the main site device 1 records the size of the section in which the associated data is stored when updating the difference information during the mirroring process (step B25 in FIG. 3). When the secondary site device 20 requests the difference data during the recovery process (step G20 in FIG. 8), the secondary site device 20 may request the data of all the sections associated with the difference information.

1 Primary site device 2 Secondary site device group 20 Secondary site device 101, 201 I / O control device 102, 202 Mirroring processing device 103, 203 Difference management device 104, 204 Disk 105, 205 Mirroring processing number holding device 106, 206 Difference information Holding device H Host device N Network

Claims (4)

A main site device with an original storage device;
A sub-site device group comprising at least one sub-site device comprising a storage device for storing a copy of the data stored in the storage device of the main site device;
A disk mirroring system comprising:
The main site device is
A mirroring processing device for assigning a mirroring processing number, which is a number updated for each mirroring processing, to a mirroring processing for storing a copy of the data in the secondary site device;
When a difference occurs due to failure in writing the copy of the data in any of the secondary site devices during the mirroring process, differential information indicating the difference including a mirroring process number corresponding to the mirroring process is generated, and A difference management device that stores the data in association with the data;
Have
The secondary site device is
A mirroring processing device that saves data transmitted from the main site device in the storage device and updates a mirroring processing number corresponding to the mirroring processing when the mirroring processing occurs,
At the time of recovery processing for matching the contents of the storage device of the secondary site device with the storage device of the main site device, the presence / absence of data to be recovered is determined based on the difference information transmitted from the main site device, and the recovery A difference management device that requests the main site device to transmit the data if there is data to be transmitted;
A disk mirroring system. The difference management device of the main site device is:
When a difference occurs due to a failure in writing a copy of a plurality of data in any of the secondary site devices during the mirroring process, the difference information is stored in association with the plurality of data,
The difference management device of the secondary site device is:
The disk mirroring system according to claim 1, wherein the main site apparatus is requested to transmit the plurality of data based on the difference information. A main site device with an original storage device;
A sub-site device group comprising at least one sub-site device comprising a storage device for storing a copy of the data stored in the storage device of the main site device;
A disk mirroring system management method comprising:
The main site device is
A mirroring process number that is a number updated for each mirroring process is assigned to a mirroring process that stores a copy of the data in the secondary site device, respectively.
When a difference occurs due to failure in writing the copy of the data in any of the secondary site devices during the mirroring process, differential information indicating the difference including a mirroring process number corresponding to the mirroring process is generated, and Save it in association with the data,
The secondary site device is
The data transmitted from the main site device is stored in the storage device, and when the mirroring process occurs, the mirroring process number corresponding to the mirroring process is updated,
At the time of recovery processing for matching the contents of the storage device of the secondary site device with the storage device of the main site device, the presence / absence of data to be recovered is determined based on the difference information transmitted from the main site device, and the recovery A method of managing a disk mirroring system that requests the main site device to transmit the data when there is data to be transmitted. The main site device is
When a difference occurs due to a failure in writing a copy of a plurality of data in any of the secondary site devices during the mirroring process, the difference information is stored in association with the plurality of data,
The secondary site device is
4. The disk mirroring system management method according to claim 3, wherein the main site apparatus is requested to transmit the plurality of data based on the difference information.

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