JP2007172646A - Data transfer control method, switch system and data control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transfer data between old and new disk apparatus without changing disk definitions of a host computer. <P>SOLUTION: Data are copied to a transfer target disk apparatus with continuing disk access from the host computer through a switch provided with on-line data transfer functions between the host computer and a data transfer source disk apparatus. After data transfer, if the host computer issues an SCSI command to identify a disk, the response of the transfer source disk apparatus is returned. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a disk device online data migration technique, that is, a control method for migrating the contents of a disk device storing data to be processed in the host computer to another disk device while the job of the host computer is substantially continued, a disk The present invention relates to a device data control method and a switch system.

  In a computer system, when updating a disk device that functions as an external storage device (old disk device or migration source disk device) to a newly connected disk device (migration destination disk device), it is used in the processing up to that point. In order to continue using the data, it is necessary to transfer the data in the old disk device to the new disk device (migration). In such a case, as a conventional general method, a method of temporarily backing up the contents of an existing disk device to a tape device or the like and restoring (writing back) after replacing the disk device is employed. Alternatively, a method is also known in which a new disk device is simultaneously connected to a host computer in addition to an existing old disk device, and the host computer replicates data from the old disk device to the new disk device. However, with these methods, the operation of the host computer is stopped for a long time. Such long-term business interruptions are unacceptable in recent data center operations characterized by non-stop operation.

  As a means for improving this, a method of transferring data from an old disk device to a new disk device by connecting the new disk device to a switch interposed between the host computer and the old disk device is disclosed in Japanese Patent Application Laid-Open No. 2005-228867. 2001-249853). In this data migration method, the switch (or storage system) is provided with a unit that replicates data from the migration source disk to the migration destination disk while continuing to access the disk device of the host computer. However, in this data migration method, it is necessary to once disconnect the connection between the existing host computer and the old disk device and insert the switch having the online data migration function. At this time, if there is only one access path between the host computer and the old disk device, it is necessary to stop the computer system.

  On the other hand, Patent Document 2 (Japanese Patent Application Laid-Open No. 11-184641) is a method in which a plurality of access paths are provided between a host computer and a disk device and data is transferred without interruption while maintaining at least one access path. Is disclosed. In this data migration method, an alternate path function provided on the host computer, that is, a function for dynamically switching the access route by managing two or more access routes between the host computer and the disk device on the host computer. Realized by. However, there are some alternate path functions of the host computer that cannot handle disk devices with different interface specifications for a specific disk device. The reason is that the alternate path function uses a SCSI response unique to the disk device in order to automatically identify a plurality of access paths to the disk device (represented as a logical unit in the SCSI protocol). That is, in this response, if consistency is not recognized in the disk unique information in the interface command, there arises a problem that access is denied.

JP2001-249853 JP 11-184641

  In the prior art as described above, when switching from the migration source disk device to the migration destination disk device, the unique information of the migration source disk (device) held as configuration information by the host computer and the migration destination disk (device) Therefore, due to this inconsistency, the host computer determines that there is a failure in the migration destination disk device and blocks the access path. As a result, the computer system goes down. There is a problem that there are concerns.

  An object of the present invention is to provide a non-stop data migration control method that does not require any stop of access from the host computer to the disk device due to the inconsistency accompanying the data migration procedure from the migration source disk device to the migration destination disk device, An object of the present invention is to provide an interface command control technique (control method and computer system) in data migration of a disk device.

  Another object of the present invention is to update (replace) a disk device having a different specification by avoiding the occurrence of a failure due to a change in disk device specific information associated with the migration from the migration source disk device to the migration destination disk device. It is an object to provide an interface command control technology in data migration that makes possible the above.

Another object of the present invention is to maintain the redundancy of the access path by allowing the above-mentioned alternate path function to function normally during and after data migration, and to control interface commands in data migration of a highly available computer system. To provide technology.
Another object of the present invention is to provide an interface command control technique in data migration of a disk device that can smoothly perform migration of a disk device shared by a plurality of host computers without stopping.

  A further object of the present invention is to provide a computer system to which the interface command control method of the magnetic disk device is applied.

To achieve the above object, the present invention provides a data migration control method for a switch system connected to an initiator that accesses a storage area and a plurality of disk devices each having a plurality of disks. Receiving a data write request relating to the storage area from the initiator, and transmitting a data write request to a first disk device included in the plurality of disk devices; A second step of transferring data stored in the disk device to a second disk device included in the plurality of disk devices, a step of receiving a data write request regarding the storage area from the initiator, and a second disk device Transmitting a data write request to the third step group comprising: And a fourth step of controlling setting or non-setting of the reserve authority for the initiator for the storage area according to whether or not the reserve authority for the other initiator is set for the storage area, and The second step is processed between the first step group and the third step group.
The present invention also relates to a data migration control method for a switch system connected to an initiator that accesses a storage area and a plurality of disk devices each having a plurality of disks, and relates to the storage area from the initiator. A first step group comprising: a step of receiving a data write request; and a step of transmitting a data write request to a first disk device included in the plurality of disk devices; A second step of transferring the stored data to the second disk device included in the plurality of disk devices, a step of receiving a data write request regarding the storage area from the initiator, and a data write request to the second disk device And a third step group comprising: And a fourth step for controlling not to set a reserve authority for another initiator for the storage area when the reserve authority for the creator is set, and the second step is a first step. It was made to be processed between the group and the third step group.

  Further, the switch system is connected to a plurality of initiators, receives a read request and / or a write request and a reserve request transmitted from the plurality of initiators, a plurality of first ports, a plurality of disks, and a plurality of disks A plurality of second ports connected to a plurality of disk devices having a disk controller for controlling reading and / or writing to the disk, and transmitting read requests and / or write requests to the plurality of disk devices; The switch system controls data transfer from the first disk device included in the plurality of disk devices to the second disk device, and is reserved by the first initiator included in the plurality of initiators. When there is access to a storage area from a second initiator included in multiple initiators In this case, the access from the second initiator is controlled exclusively.

  A data control method in a switch system connected to a plurality of disk devices having a plurality of disks and a disk control unit that controls reading and / or writing to the plurality of disks, and a plurality of initiators, A read request and / or write request transmitted from an initiator included in a plurality of initiators is received, a read request and / or a write request is transmitted to a disk device included in a plurality of disk devices, and the plurality of disk devices are transmitted. The migration of data from the first disk device included to the second disk device is controlled, and the storage areas reserved by the first initiator included in the plurality of initiators are included in the plurality of initiators. Receive access sent from the second initiator, and from the second initiator The access to be signal was set to exclusive control.

  Furthermore, a data control method in a switch system connected to a plurality of disk devices having a plurality of disks and a disk control unit for controlling reading to the plurality of disks, and a plurality of initiators, Receiving a read request transmitted from the initiator included in the first disk device, controlling data migration from the first disk device to the second disk device included in the plurality of disk devices, and from the first disk device to the second disk device. When a read request is received from the initiator before the data is transferred to the disk device, the read request is transmitted to the first disk device, and the data from the first disk device to the second disk device is transmitted. If a read request is received from the initiator during migration, a read request is sent to the first disk device When a read request is received from the initiator after the data transfer from the first disk device to the second disk device is completed, the read request is transmitted to the second disk device and sent to a plurality of initiators. An access transmitted from the second initiator included in the plurality of initiators is received with respect to the storage area reserved by the included first initiator, and the access transmitted from the second initiator is exclusively controlled. I made it.

  According to the disk device data migration method of the present invention, the host recognizes that the old disk is connected during and after data migration from the old disk device to the new disk device. Is unnecessary, and the effect that the operation on the host can be continued is obtained.

  Also, in a system in which the host and the old disk unit are connected with multiple redundant access paths, there is no need to stop access to the disk unit from the host in the data migration procedure, and even after data migration Since the host can continuously use a plurality of access paths, data migration can be performed without stopping access, and the fault tolerance of the access path can be maintained.

  Further, in a cluster system in which a plurality of hosts share an old disk, the exclusive information of the disk device is also transferred, so that there is an effect that smooth data transfer can be performed without stopping while maintaining the cluster.

  In addition, after data migration, there is an effect that the old disk can be diverted to store other data.

The disk device interface command control method and computer system according to the present invention will be described below in more detail with reference to the embodiments of the present invention shown in FIGS.
(1) Computer System Configuration FIG. 1 (a) shows a computer system configuration example before data migration. The host computer 1 is connected to the migration source disk device 2 using access paths 3 and 4. The access paths 3 and 4 are parallel SCSI or fiber channel based on the SCSI standard.

  FIG. 1B shows a computer system configuration example during and after data migration. The switch 5 is connected to the host computer 1 using the access paths 3a and 4a, and is connected to the migration source disk device 2 using the access paths 3b and 4b. The access paths 3a and 4a and 3b and 4b are parallel SCSI or fiber channel based on the SCSI standard. These 3a and 4a and 3b and 4b are access paths after switching connection.

  The migration destination disk device 6 and the switch 5 are connected by access paths 7 and 8. The access paths 7 and 8 are parallel SCSI or fiber channel based on the SCSI standard. In the present invention, since data migration is performed from the migration source disk device 2 to the migration destination disk device 6, the number of hosts is not limited in carrying out the present invention.

  The host interface control unit 9 is connected to the access paths 3a and 4a via the ports 15 and 16, and controls the reception and transmission of the SCSI command with the host computer 1. The host interface control unit 9 is connected to the disk interface control units 13 and 14 and the reserve simulation unit 10 through internal paths 21, 29, and 22, respectively.

  The disk interface control unit 13 is connected to the access paths 3b and 4b via the ports 17 and 18, and controls the reception and transmission of the SCSI command with the migration source disk 2. The disk interface control unit 13 is connected to the reserve simulation unit 10, the SCSI command control unit 11, and the online data migration unit 12 through internal paths 23, 25, and 27, respectively.

  The disk interface control unit 14 is connected to the access paths 7 and 8 via the ports 19 and 20 and controls the reception and transmission of the SCSI command with the migration destination disk 6. The disk interface control unit 14 is connected to the SCSI command control unit 11 and the online data migration unit 12 through internal paths 26 and 28, respectively.

The Reserve simulation unit 10 receives the SCSI command issued by the host computer 1 from the host interface control unit 9 via the internal path 22 and performs exclusive control on access from the host computer according to the SCSI command related to reserve and release. (In the embodiment of FIG. 1B, one host computer 1 is shown, but in the present invention, there is no limit to the number of host computers to be connected.)
The SCSI command control unit 11 receives the SCSI command from the host computer 1 via the host interface control unit 9 and the Reserve simulation unit 10, and the migration source disk device 2 and the migration via the disk interface control units 13 and 14. The SCSI command is transferred to the destination disk device 6. The responses from the migration source disk device 2 and the migration destination disk device 6 are transferred to the host computer 1 through the reverse path. The SCSI command control unit 11 has a function of classifying SCSI commands from the host computer 1 and transferring them to the migration source disk device 2 or the migration destination disk device 6. The operation will be described later with reference to FIGS.

  The online data migration unit 12 in FIG. 1B has a function of autonomously replicating data stored in the disk device. In the data migration, the disk interface control unit 13 is transferred from the migration source disk device 2. The data is read via the disk interface controller 14 via the disk interface controller 14.

(2) Interface Command Control Procedure in Data Migration An example of data migration processing in the computer system having the configuration illustrated in FIG. 1 will be described with reference to the flowcharts in FIGS. FIG. 5 shows that the data migration process proceeds in the order of steps 51, 52, 53, 54, and 55 in the embodiment of FIG. 1, and in the following description (step 51), (step 52),. . (Step 55). FIG. 6 shows procedures 61 to 64 of maintenance personnel operations executed in step 52 of FIG.

Before the start of data migration, the host computer 1 accesses the migration source disk 2 using the access paths 3 and 4 as shown in FIG.
First, the maintenance staff connects the migration destination disk device 6 to the switch 5 using the access paths 7 and 8 (step 51).
Next, the maintenance staff operates in accordance with the procedures 61 to 64 shown in FIG. 6 in order to connect the migration source disk device 2 to the switch 5 (step 52). The maintenance staff switches and connects the access path 4 to the new access paths 4a and 4b (step 61 in step 52). At this time, the host computer 1 detects the switching of the access path 4, places the access path 4 in an offline state, and continues to access the migration source disk device 2 using the access path 3. Next, the host computer 1 is operated to bring the access path 4a online (procedure 62 in step 52).

FIG. 2 shows the state at this time, and the host computer 1 and the migration source disk device 2 are logically connected by SCSI data paths 30 and 31.
Next, the access path 3 is switched and connected to the new access paths 3a and 3b (step 63 in step 52). Next, the host computer 1 is operated to bring the access path 3a online (procedure 62 in step 52).
As a result, the host computer 1, the switch 5, and the migration source disk 2 are connected as shown in FIG. 1b, and the host computer 1 accesses the migration source disk device 2 via the switch 5.

  Next, in step 53 of FIG. 5, the process related to SCSI reserve is transferred from the migration source disk device 2 to the reserve simulation unit 10. Specifically, the Reserve simulation unit 10 accesses the migration source disk device 2 through the internal path 23, checks the reserved state of the migration source disk device 2, sets that state as the initial state of the Reserve simulation unit 10, and then transfers the migration source disk device 2. The reserved state of the disk device 2 is released. After that, the Reserve simulation unit 10 performs processing of SCSI commands related to reserves such as Reserve and Release received from the host, and exclusive processing of access from other host computers (other initiators) to the reserved disk. Do. Release of the reserved state of the migration source disk device in the processing of step 53 must be performed before the online data migration (step 54) is executed. That is, in the state where the migration source disk device 2 is reserved by the Reserve command from the host computer, the process of reading data from the migration source disk device 2 for online data migration is hindered. Therefore, by providing the Reserve simulation unit 10 above the online data migration unit 12, the migration source disk device can be accessed without being reserved.

  Next, the online data migration unit 12 copies data from the migration source disk device 2 to the migration destination disk device 6 (step 54). Here, the main data flow during data migration will be described with reference to FIG. The host computer 1 and the migration source disk device 2 are logically connected by a SCSI data path 32, and the access to the migration source disk device 2 from the host computer 1 is continued. In parallel with this, the online data migration unit 12 executes data copying from the migration source disk device 2 to the migration destination disk device 6 as indicated by the SCSI data path 33.

  Next, when the online data migration processing is completed, the SCSI command control unit 11 switches the SCSI command related to disk read and write from the host computer 1 to the migration destination disk 6 (step 55). Here, the main data flow after data migration will be described with reference to FIG. The SCSI commands related to Read and Write issued by the host computer 1 are transferred from the SCSI command control unit 11 through the internal path 26 and the disk interface control unit 14 as shown by the SCSI data path 35 in FIG. Passed to 6. The SCSI command related to Read and Write from the host computer 1 is not issued to the migration source disk device 2.

  The SCSI command control unit 11 determines the SCSI command for identifying the disk device issued by the host computer 1, that is, the Inquiry command and the Mode Sense type SCSI command not defined by the SCSI standard specification. And subsequently issued to the migration source disk device 2 (indicated by the SCSI data path 34 in FIG. 4). As a result, the processing related to actual read and write is performed in the migration destination disk device 6, but the host computer 1 recognizes that the migration source disk device 2 is still connected, so the data migration is completed without stopping. can do.

  When such data migration is executed by a plurality of host computers, the migration source magnetic disk device is shared by the plurality of host computers. In addition, when there are a plurality of migration source magnetic disk devices, a plurality of magnetic disk devices are shared.

FIG. 7 shows a SCSI command type table. In this table, the SCSI command name “Inquiry” (operation code 12 _H ) and the SCSI command of “Mode Sense” (operation code 1A _H system) not defined in the SCSI standard specifications are command types set unique to the disk device. . In data access after data migration between magnetic disk devices, there is a concern that such a mismatch in command type is recognized by the host computer as inconsistency in disk exchange information, and access to the data after migration is denied. However, according to the interface command control method and computer system of the present invention, it has been confirmed that such inconsistency recognition is avoided and data access after migration is performed smoothly.

  FIG. 8 shows a specific procedure of the interface command control method of the present invention for avoiding such inconsistency recognition.

  FIG. 9 shows a situation in which unique information corresponding to a command type set unique to a magnetic disk device in the computer system of the present invention is stored as a memory.

  In the above embodiment, an example is described in which the switch 5 is used for data migration. However, the present invention is not limited to this example, and the disk device or disk controller (information 201, memory 202 unique to the migration source disk device in FIG. It is also preferable to perform data migration using a general name of a portion including the port control unit 203, the CPU 204, and the disk control unit 205.

  As described above, according to the present invention, there is no need to stop access from the host computer to the disk device in the data migration procedure from the migration source disk device to the migration destination disk device, and data migration without interruption is possible. .

  In addition, it is possible to avoid the occurrence of failures due to changes in disk device specific information, etc. associated with the migration from the migration source disk device to the migration destination disk device. .

  In addition, redundancy of the access path between the host computer and the switch and between the switch and the disk device is maintained, and the data migration of the highly available computer system and the operation after the data migration can be performed.

  Furthermore, even in the case of a disk device shared by a plurality of host computers, a completely non-stop system or later can be realized by providing a function for simulating reserve processing.

  Although the invention made by the present inventors has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

  For example, although an example of data migration as a switch function has been described, the present invention can be widely applied to a disk array (RAID) subsystem including an equivalent function. It is also possible to divert the migration source disk after data migration to store data used by the switch or disk array subsystem.

It is a block diagram of a computer system for explaining an embodiment of a data migration method according to the present invention. It is a figure for demonstrating the process in which the switch in this invention is inserted between a host computer and a transfer source disk apparatus. It is a figure for demonstrating the data flow in the online data transfer process in this invention. It is a figure for demonstrating the flow of the data after completion of online data transfer in this invention. It is a flowchart figure for demonstrating the procedure of the data transfer in this invention. It is a flowchart for demonstrating the operation procedure which connects the migration source disk apparatus in this invention to a switch. It is a figure which shows a SCSI command classification table. It is a flowchart for determining whether the type of the SCSI command from the host computer in the present invention is “disk specific”. It is a figure which shows the structural example of the magnetic disc unit in the computer system of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Host computer, 2 ... Migration source disk unit, 3, 4 ... Access path of migration source disk unit, 3a, 4a ... Access path between host computer and switch, 3b, 4b ... Access between migration source disk unit and switch Path 5, switch 6, migration destination disk device 7, 8, access path of migration destination disk device 9, host interface control unit 10, reserve simulation unit 11, SCSI command control unit 12, online data migration , 13, 14 ... disk interface controller, 15 to 20 ... ports, 21 to 29 ... internal paths, 30, 31, 32, 34 ... SCSI data path between the host computer and the migration source disk device, 33 ... online data SCSI data path for migration processing, 35 ... SCSI data path between the host computer and the migration destination disk device, 70 ... SCSI command type Table: 71 ... SCSI operation code, 72 ... Page code, 73 ... Command name, 74 ... SCSI command type, 201 ... Information specific to the migration source disk device, 202 ... Memory, 203 ... Port control unit, 204 ... CPU, 205: Disk control unit, 210 ... Disk unit, 211 ... Disk, 601 ... Information specific to the migration destination disk device, 602 ... Memory, 603 ... Port control unit, 604 ... CPU, 605 ... Disk control unit, 610 ... Disk unit 611 disk.

Claims (30)

A data migration control method for a switch system connected to an initiator that accesses a storage area and a plurality of disk devices each having a plurality of disks,
Receiving a data write request related to the storage area from the initiator; and transmitting a data write request to a first disk device included in the plurality of disk devices;
A second step of migrating data stored in the first disk device to a second disk device included in the plurality of disk devices;
Receiving a data write request relating to the storage area from the initiator; and transmitting a data write request to the second disk device; a third step group comprising:
And a fourth step of controlling setting or non-setting of the reserve authority for the initiator for the storage area according to whether or not the reserve authority for the other initiator is set for the storage area. And
The second step is processed between the first step group and the third step group.
A data migration control method characterized by the above. A data migration control method for a switch system connected to an initiator that accesses a storage area and a plurality of disk devices each having a plurality of disks,
Receiving a data write request related to the storage area from the initiator; and transmitting a data write request to a first disk device included in the plurality of disk devices;
A second step of migrating data stored in the first disk device to a second disk device included in the plurality of disk devices;
Receiving a data write request relating to the storage area from the initiator; and transmitting a data write request to the second disk device; a third step group comprising:
A fourth step of controlling not to set a reserve authority for another initiator for the storage area when a reserve authority for the initiator is set for the storage area; and
The second step is processed between the first step group and the third step group.
A data migration control method characterized by the above. The data migration control method according to claim 1 or 2,
At least during the processing of the second step, the fourth step is processed;
A data migration control method characterized by the above. The data migration control method according to claim 1 or 3,
The fourth step is performed based on a reserve request transmitted from the initiator.
A data migration control method characterized by the above. A data migration control method according to claim 2 or 3,
The fourth step is performed based on a reserve request transmitted from the other initiator.
A data migration control method characterized by the above. A data migration control method according to any one of claims 1 to 5,
A fifth step of releasing reserve authority for the initiator set for the storage area;
A data migration control method characterized by the above. A data migration control method according to any one of claims 1 to 6,
The fifth step is performed based on a release request of the SCSI standard.
A data migration control method characterized by the above. A data migration control method according to any one of claims 1 to 7,
The fourth step is performed based on a reservation request of the SCSI standard.
A data migration control method characterized by the above. A switch system,
A plurality of first ports connected to a plurality of initiators and receiving a read request and / or a write request and a reserve request transmitted from the plurality of initiators;
Connected to a plurality of disk devices having a plurality of disks and a disk control unit for controlling reading and / or writing to the plurality of disks, and transmits a read request and / or a write request to the plurality of disk devices. A plurality of second ports;
The switch system controls data migration from a first disk device included in the plurality of disk devices to a second disk device, and is reserved by a first initiator included in the plurality of initiators. The access from the second initiator is exclusively controlled when there is an access to the storage area from the second initiator included in the plurality of initiators.
A switch system characterized by that. The switch system according to claim 9, wherein
A controller that controls the migration of the data from the first disk device to the second disk device and the exclusive control of the access from the second initiator;
A switch system characterized by that. The switch system according to claim 9 or 10, wherein
The switch system reserves a storage area by the first initiator in accordance with a reserve request transmitted from the first initiator.
A switch system characterized by that. The switch system according to any one of claims 9 to 11,
The switch system releases a storage area reserved by the first initiator according to a release request transmitted from the first initiator.
A switch system characterized by that. The switch system according to any one of claims 1 to 12,
In response to a read request received from the first initiator during the migration of the data from the first disk device to the second disk device, the switch system is responsive to the first disk device. To send a read request,
A switch system characterized by that. The switch system according to any one of claims 9 to 13,
In response to a read request received from the first initiator after the migration of the data from the first disk device to the second disk device is completed, the switch system sends the data to the second disk device. To send a read request to
A switch system characterized by that. The switch system according to any one of claims 9 to 14,
In response to a write request received from the first initiator after the migration of the data from the first disk device to the second disk device is completed, the switch system sends the data to the second disk device. Send a write request to the
A switch system characterized by that. The switch system according to any one of claims 9 to 15,
The switch system causes the first initiator to recognize the same storage area during and after the migration of the data from the first disk device to the second disk device.
A switch system characterized by that. The switch system according to any one of claims 9 to 16,
At least one first port of the plurality of first ports is involved in the data migration during the data migration from the first disk device to the second disk device. Receiving a read request and / or a write request to the storage area from the first initiator;
A switch system characterized by that. The switch system according to any one of claims 9 to 17,
A first processing unit that controls migration of the data from the first disk device to the second disk device; a second processing unit that performs exclusive control of the access from the second initiator; Having a control unit having
A switch system characterized by that. A data control method in a switch system connected to a plurality of disk devices having a plurality of disks and a disk control unit that controls reading and / or writing to the plurality of disks, and a plurality of initiators,
Receiving a read request and / or a write request transmitted from an initiator included in the plurality of initiators;
Transmitting a read request and / or a write request to a disk device included in the plurality of disk devices;
Controlling data migration from a first disk device to a second disk device included in the plurality of disk devices;
Receiving an access transmitted from a second initiator included in the plurality of initiators to a storage area reserved by a first initiator included in the plurality of initiators;
Exclusive control of the access transmitted from the second initiator;
A data control method characterized by the above. A data control method in a switch system connected to a plurality of disk devices having a plurality of disks and a disk control unit for controlling reading to the plurality of disks, and a plurality of initiators,
Receiving a read request transmitted from an initiator included in the plurality of initiators;
Controlling data migration from a first disk device to a second disk device included in the plurality of disk devices;
When the read request is received from the initiator before the data is transferred from the first disk device to the second disk device, the read request is transmitted to the first disk device;
When the read request is received from the initiator during the data transfer from the first disk device to the second disk device, the read request is transmitted to the first disk device;
When the read request is received from the initiator after the data migration from the first disk device to the second disk device is completed, the read request is transmitted to the second disk device. ,
Receiving an access transmitted from a second initiator included in the plurality of initiators to a storage area reserved by a first initiator included in the plurality of initiators;
Exclusive control of the access transmitted from the second initiator;
A data control method characterized by the above. The data control method according to claim 19 or 20,
The data migration control from the first disk device to the second disk device and the exclusive control of the access from the second initiator are controlled by the control unit of the switch system. is there,
A data control method characterized by the above. The data control method according to claim 19 to 21, comprising:
Receiving a reserve request transmitted from the first initiator;
In accordance with the received reserve request, reserve the storage area by the first initiator.
A data control method characterized by the above. A data control method according to any one of claims 19 to 22,
Receiving a release request sent from the first initiator;
Releasing a storage area reserved by the first initiator according to the received release request;
A data control method characterized by the above. A data control method according to any one of claims 19, 21 to 23, wherein
Receiving a read request from the first initiator during the data migration from the first disk device to the second disk device;
Transmitting a read request to the first disk device in response to the read request received from the first initiator;
A data control method characterized by the above. A data control method according to any one of claims 19, 21 to 24,
After the data migration from the first disk device to the second disk device is completed, a read request is received from the first initiator,
In response to the read request received from the first initiator, a read request is transmitted to the second disk device.
A data control method characterized by the above. A data control method according to any one of claims 19 to 25,
After the migration of the data from the first disk device to the second disk device is completed, a write request is received from the first initiator;
Transmitting a write request to the second disk device in response to the write request received from the first initiator;
A data control method characterized by the above. A data control method according to any one of claims 19 to 26, wherein:
The switch system causes the first initiator to recognize the same storage area during and after the migration of the data from the first disk device to the second disk device.
A data control method characterized by the above. A data control method according to any one of claims 19 to 27,
During the data transfer from the first disk device to the second disk device, a read request and / or a write request to the storage area related to the data transfer is received from the first initiator. To
A data control method characterized by the above. A data control method according to any one of claims 19 to 28,
The switch system includes a first processing unit that controls the migration of the data from the first disk device to the second disk device, and a second that performs exclusive control of the access from the second initiator. And a processing unit having a control unit,
A data control method characterized by the above. Connected to the initiator accessing the storage area,
A data migration control method by the control unit in a disk device having a plurality of storage devices and a control unit that controls access to the storage area associated with the plurality of storage devices,
Receiving a data write request related to the storage area from the initiator; and transmitting a data write request to a first storage device included in the plurality of storage devices;
A second step of migrating data stored in the first storage device to a second storage device included in the plurality of storage devices;
Receiving a data write request related to the storage area from the initiator; and transmitting a data write request to a second storage device included in the plurality of storage devices;
Have
The second step is processed between the first step group and the third step group.
A data migration control method characterized by the above.

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