JP2007073075A - Storage device subsystem having volume duplication function and computer system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obviate the need for management of volume on the side of a host computer or adjustment of volume use between host computers, by allowing the volume to be efficiently used, in a storage device subsystem having a volume duplication function. <P>SOLUTION: A volume for storing a copy is made selectable when an instruction for copy creation is received from the host. The volume usable for the copy is reported to the host and made to be selected on the host side. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a storage device subsystem having a volume replication function, and is a storage device subsystem having a function of creating a copy of a volume without using a host in the same storage device subsystem. Related to the selection of the copy destination volume.

  As a technology to back up consistent and consistent data without stopping applications or databases for a long time, create a replica of the data in the volume in the storage subsystem and back up from the destination It has been known. The advantage of this method is that it is not necessary to stop online because it is duplicated from the original volume and used as a backup target, and it is easy to maintain the integrity of the backup data.

Hereinafter, the volume replication technique will be described with reference to FIG.
FIG. 25 is a diagram showing an outline of the volume replication technique.

When using this volume duplication technique, the user takes the following procedure to back up consistent and consistent data.
(Step 1) Designate a volume for storing data to be backed up (this volume is referred to as “primary volume”) and a volume for storing a copy of data (this volume is referred to as “secondary volume”). Is instructed to create a copy. A pair of a primary volume and a secondary volume is called a “pair”, and generating a copy is called a “pair formation”.
(Step 2) Upon receipt of the pair formation instruction, the storage subsystem reads data from the primary volume, creates a replica, and stores it in the secondary volume (this is referred to as “formation copy”). Further, when the host writes to the primary volume, the storage subsystem writes the write data to the primary volume also to the secondary volume (this is referred to as “update copy”).
(Step 3) When the formation copy in Step 2 is completed and a time suitable for obtaining a backup such as application termination or database termination has been reached, a “pair split” request is issued to the storage device sub Publish to the system. When the “pair split” request is received, the storage subsystem stops the update copy. Thereafter, even if writing to the primary volume is not reflected in the secondary volume, the secondary volume is frozen to the data at the time when the “pair split” request is received.
(Step 4) The data in the secondary volume is backed up to a magnetic tape (MT) or the like. Of course, even during this time, it is possible to refer / update data in the primary volume by operating applications and databases.
(Step 5) When the backup is completed, a “pair release” request is issued to the storage subsystem. When receiving the “pair cancel” request, the storage subsystem cancels the relationship between the primary volume and secondary volume pair.

  When performing operations such as backup using the volume replication technology described in the above-mentioned prior art, the simplest volume management is to assign a secondary volume in advance for each volume that stores user data. Is the method. However, this method has a problem that it is necessary to allocate half of the volume in the storage device subsystem for the secondary volume, and the volume usage efficiency is poor.

  In order to use the volume efficiently, there is a method in which one or more volumes are prepared for the secondary volume and appropriately selected and used when the secondary volume becomes necessary. In order to use this method, the host needs to manage volume usage information such as which of the prepared volumes is being used.

  Currently, a connection form in which a plurality of hosts are connected to one storage device subsystem has become common. In the case of this connection form, a mechanism is required in which a plurality of hosts share the volume usage information using a network or the like and dynamically adjust the volume usage, and the OS (operating system) must have such a mechanism. There was a problem that management became complicated. Further, there are many cases in which different OSs are operating on the plurality of hosts, and it is necessary for the user to prepare a mechanism corresponding to each OS.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to efficiently use a volume when performing operations such as performing backup using the volume duplication technology described in the prior art. It is to provide functions that can be performed.

  It is a further object of the present invention to provide a function that eliminates the need for volume management on the host side and adjustment of volume usage between hosts when using the volume replication technology.

  In order to achieve the above object, the configuration of the storage device subsystem having a volume duplication function according to the present invention includes a plurality of volumes to be accessed from the host in the storage device subsystem connected to the host. And a processor that accesses the plurality of volumes, and the processor is designated when an instruction to duplicate the first volume is received from the outside by designating the first volume to be a replication source. The second volume for storing the copy is determined based on the information of the first volume.

  More specifically, in the storage subsystem having the volume replication function, when replication from the first volume to the second volume is completed, the second volume is released.

  More specifically, in the storage subsystem having the volume replication function, when the second volume is selected, a volume larger than the capacity of the first volume designated by the host is selected.

  More specifically, in the storage subsystem having the volume replication function, if an instruction to change the attribute of whether or not the volume can be the replication destination is received from the outside, can the volume become the replication destination volume? The attribute of “no” is rewritten to change the availability of use of the volume as the replication destination.

  In order to achieve the above object, the configuration of the computer system according to the present invention includes a host and a computer system connected to the host, wherein the storage device subsystem is an access target from the host and a secondary volume. A plurality of volumes in which volume information including an attribute indicating whether or not can be set, a memory storing the volume information, and a processor connected to the memory and accessing the plurality of volumes, The processor refers to the attribute of whether or not it can become the secondary volume when a request is received from the outside, and reports the secondary volume that can be used to store the replica to the outside.

  More specifically, in the computer system, a volume for storing a replica is selected from the secondary volumes that can be used to store the reported replica, and a copy instruction is given to the storage subsystem. Is.

  Due to the configuration of the storage device subsystem, when using volume replication technology, a volume group reserved in advance as a secondary volume is used as a secondary volume, and when replication is no longer necessary, the volume group is returned to the volume group. Can be reused. This makes it possible to effectively use the volume in the storage device subsystem.

  Further, with the configuration of the storage device subsystem, when the pair is formed, the secondary volume is automatically selected on the storage device subsystem side, and the management of the volume on the host side is unnecessary. In particular, when multiple hosts are connected to a single storage subsystem and volume replication technology is used on each host, volume adjustment that was previously required between hosts using a network or the like is no longer necessary. Become.

  Further, the configuration of the computer system allows the storage subsystem to report a volume that can be used as a secondary volume when a pair is formed, thereby eliminating the need for volume management on the host side. In particular, when multiple hosts are connected to a single storage subsystem and volume replication technology is used on each host, volume adjustment that was previously required between hosts using a network or the like is no longer necessary. Become.

  Further, when the capacity of the primary volume and the copy destination secondary volume is different due to the configuration of the storage device subsystem, the storage area is effectively utilized by adjusting the allocation so that the volume capacities are equal. be able to.

  According to the present invention, it is possible to provide a function capable of efficiently using a volume when performing an operation for performing backup using the volume replication technology described in the related art.

  Furthermore, according to the present invention, it is possible to provide a function that eliminates the need for volume management on the host side and adjustment of volume usage between hosts when using the volume replication technology.

  Embodiments according to the present invention will be described below with reference to FIGS.

Embodiment 1
A first embodiment according to the present invention will be described below with reference to FIGS.
(I) System Configuration First, the system configuration of the computer system according to the present embodiment will be described with reference to FIG.
FIG. 1 is a block diagram showing a system configuration according to the first embodiment of the present invention.

  This system comprises a host 100 and a disk subsystem 101 which is a storage subsystem.

  The host 100 is a computer that causes an OS (operating system) and applications to be executed by a CPU. The OS also includes modules that control input / output devices and auxiliary storage devices.

  The disk subsystem 101 is a device for writing and reading data and programs on a magnetic disk which is an auxiliary storage device in response to a command from the host. The disk subsystem 101 includes a host interface 102, a control processor 107, a control memory 111, a volume 113, and a volume 1 volume access mechanism 112 as shown in FIG.

  The host interface 102 is a part that controls an interface that relays information exchange with the host 100. The control processor 107 is a processor for executing various processes (a pair formation process 103, a pair release process 104, a volume attribute change process 105, a pair status report process 106, etc.) as shown in FIG. In other words, the disk subsystem 101 of the present invention has considerable intelligence and can operate independently of the host. The control memory 111 is a memory for storing control information (volume information 108, pair information 109, etc.) necessary for the control processor 107 to execute processing.

The volume 113 is called a magnetic disk for storing data as a logical management unit, and a plurality of physical magnetic disks may be stored in one volume. The magnetic disk may be a single volume. The volume 113 has a volume number as an identifier for identifying each, and is thereby accessed from the host 100 and the disk subsystem 101. The volume access mechanism 112 is a mechanism for accessing the volume 113 and operates according to an instruction from the control processor 107.
(II) Data Structure Next, a data structure used in the system according to the present embodiment will be described with reference to FIGS.
FIG. 2 is a schematic diagram showing volume information according to the first embodiment.
FIG. 3 is a schematic diagram showing pair information.
FIG. 4 is a schematic diagram showing parameters of a pair formation command.
FIG. 5 is a schematic diagram showing parameters of the pair release command.
FIG. 6 is a schematic diagram showing parameters of a volume attribute change command.

  The volume information shown in FIG. 2 stores information about each volume 113 and is held in the control memory 111 of the disk subsystem 101. The volume information 108 includes a volume number 200, a capacity 201, an attribute 202, and a pair presence / absence flag 203.

  The volume number 200 is an identifier for identifying the volume 113. The capacity 201 indicates the amount of data that can be stored in the corresponding volume 113. The attribute 202 is information indicating whether the volume 113 is used for storing user data or used as a secondary volume, and takes a value of “normal volume” or “secondary volume”. When the attribute 202 is “normal volume”, this indicates that the volume 113 is used for storing user data. When the attribute 202 is “secondary volume”, this indicates that the volume 113 is being used as a secondary volume or is a volume 113 to be used. The pair presence / absence flag 203 is a flag indicating whether or not the volume 113 is performing pair formation, and takes a value of either “pair formation in progress” or “no pair formation”. When the pair presence / absence flag 203 is “pair formation”, this indicates that the volume 113 is forming a pair, and when the pair presence / absence flag 203 is “no pair formation”, the volume 113 forms a pair. Indicates that it has not.

The value of each record given as an example in FIG. 2 indicates the following.
(1) The volume 113 whose volume number is 0 has a capacity of 1000 MB, is used for storing user data, and forms a pair.
(2) The volume 113 whose volume number is 1 has a capacity of 1500 MB and is scheduled to be used as a secondary volume. Pairs are not formed.

  The pair information 109 shown in FIG. 3 is information for managing volume pairs, and includes a primary volume number 300, a secondary volume number 302, a copy pointer 303, and a pair status 304.

  The primary volume number 300 indicates the volume number of the primary volume of the pair, and the secondary volume number 301 indicates the volume number of the secondary volume of the pair. The copy pointer 302 is information indicating the progress of formation copying, and is indicated by a percentage from 0% to 100%. That is, 0% when copying is started, and 100% when copying is completed.

The pair status 303 is information used for controlling the pair from the host 100 or the disk subsystem 101, and defines the following four types (see also FIG. 25).
1. (Simplex state)
A state where no pair is formed.
2. (Duplex-Pending state)
A pair is formed, and both the formation copy and the update copy are performed or may be performed.
3. (Duplex state)
A pair is formed, the formation copy is finished, and only the update copy is performed or may be performed.
4). (Split state)
Status from pair split to pair release.

  Here, it should be noted that in the duplex-pending state, since the formation copy is in progress, the host 100 cannot issue a pair split command and can issue a pair split command in the duplex state. .

  Next, a command sent from the host 100 to give a command from the disk subsystem 101 will be described.

  The pair creation command is a command that the host 100 issues to the disk subsystem 101 when creating a volume pair. The disk subsystem 101 receives this command, selects the volume 113 to be the secondary volume, and forms a pair with the designated primary volume. Details of this processing will be described later using a processing flow.

  The pair formation command parameters shown in FIG. 4 are composed of a primary volume number 400 and a secondary volume condition 401. The primary volume number 400 is a volume number that becomes a paired primary volume. The secondary volume condition 401 indicates the condition of the volume 113 to be the secondary volume, and takes either “same capacity” or “no condition” value. When specifying that the volume 113 having the same capacity as the volume 113 specified by the primary volume number 400 is the secondary volume, the host 100 sets the secondary volume condition 401 to “same capacity” and issues a command. When designating that the volume 113 having the same capacity as the primary volume number 400 or having a larger capacity as the secondary volume is designated as the secondary volume, the host 100 sets “no condition” in the secondary volume condition 401 to execute the command Issue.

  Note that the parameter of this pair formation command does not include a secondary volume number, and it is the disk subsystem 101 that selects which secondary volume to select when forming a pair.

  Next, the pair release command is a command that the host 100 issues to the disk subsystem 101 when releasing a pair for a volume in which a pair is formed.

  When the disk subsystem 101 receives this command, the pair formed is disconnected and the pair is released. Details of this processing will be described later using a processing flow.

  The parameters of the pair release command shown in FIG. 5 include a primary volume number 500, a secondary volume number 501, and a post-pair release state 502. The primary volume number 500 indicates the volume number of the primary volume, and the secondary volume number 501 indicates the volume number of the secondary volume. A pair to be released is specified by the primary volume number 500 and the secondary volume number 501. Among these, the secondary volume number 501 can be known from the report of the disk subsystem 101.

  The state after pair cancellation 502 specifies the attribute of the secondary volume after the pair cancellation, and takes the value of “normal volume” or “secondary volume”. When “secondary volume” is designated, this indicates that the volume is used as a secondary volume, and when it is used to hold other user data, “normal volume” is designated.

  Next, the volume attribute change command is a command that the host 100 issues to the disk subsystem 101 when the attribute of the volume 113 (normal volume or secondary volume) is changed. This command is issued when a situation occurs in which the allocation of the secondary volume is too large and the volume for storing user data is insufficient, or vice versa.

  When the disk subsystem 101 receives this command, the attribute of the volume 113 is changed according to the parameter. Details of this processing will be described later using a processing flow.

The parameters of the volume attribute change command shown in FIG. 6 include a volume number 600 and a post-change attribute 601. The volume number 600 indicates the volume number of the volume 113 whose attribute is to be changed. The post-change attribute 601 indicates an attribute to be set, and takes a value of “normal volume” or “secondary volume”.
(III) System Operation Next, the system operation according to the present embodiment will be described with reference to FIGS.
FIG. 7 is a diagram showing a command sequence exchanged between the host 100 and the disk subsystem 101 in the first embodiment of the present invention.
FIG. 8 is a flowchart showing processing of the disk subsystem 101 when a pair formation command is issued in the first embodiment of the present invention.
FIG. 9 is a flowchart showing processing of the disk subsystem 101 when a pair release command is issued in the first embodiment of the present invention.
FIG. 10 is a flowchart showing processing of the disk subsystem 101 when an attribute change command is issued in the first embodiment of the present invention.
FIG. 11 is a flowchart showing processing of the disk subsystem 101 when a pair status report request command is issued in the first embodiment of the present invention.

  First, the command sequence exchanged between the host 100 and the disk subsystem 101 will be described with reference to FIG. 7, and the outline of the operation of the system will be clarified.

  Since it is necessary to form a pair for backup, such as when the backup schedule time comes or the operator manually inputs a backup command from the terminal, the host 100 forms a pair with the disk subsystem 101. A command is issued (sq01).

  Next, the host 100 designates the primary volume number and issues a bare state report request command (sq02). The disk subsystem 101 receives this command and transmits a pair status report (sq03). This is the same as the pair information shown in FIG. In this pair status report, the secondary volume number is returned, so the host stores it. This is because the parameter is specified when releasing the pair.

  Thereafter, a pair status report request command is periodically issued from the host 100 (sq04). This is because the host 100 knows the timing for releasing the pair. That is, when the pair status of the pair status report from the disk subsystem 101 is the “duplex-pending status” described above, the host 100 does not issue the pair release command, but the pair status report report from the disk subsystem 101. When the pair status of is “duplex status” (sq05), a pair release command is issued.

  When the host 100 can issue the pair release command, the secondary volume number already received from the desk subsystem 101 is designated as a parameter and the pair release command is issued (sq06).

  Further, when it becomes necessary to store user data, and the volume having the normal volume attribute becomes insufficient, the host 100 assigns the volume having the secondary volume attribute to the disk subsystem 101 with the normal volume attribute. An attribute change command is issued (sq10).

  On the other hand, when a volume having a secondary volume attribute for forming a pair becomes insufficient to perform backup, the host 100 assigns a volume having a normal volume attribute to the disk subsystem 101 as a secondary volume. In order to have an attribute, an attribute change command is issued (sq11).

  Next, each process of the disk subsystem 101 will be described.

  First, the processing of the disk subsystem 101 when the host 100 issues a pair formation command to the disk subsystem 101 will be described with reference to the flowchart of FIG.

  When receiving a pair formation command from the host 100 via the host interface 102, the control processor 107 of the disk subsystem 101 starts a pair formation process 103.

  First, the control processor 107 searches for an unused secondary volume with the same capacity as the primary volume (S700). That is, the capacity 201 of the volume 113 to be the primary volume is calculated from the primary volume number 400 of the parameter of the pair creation command received from the host 100 and the volume information 108. Next, a volume 113 having the same capacity 201 as the calculated capacity 201, the attribute 202 is “secondary volume”, and the pair formation presence / absence flag 203 is “no pair formation” is searched for.

  As a result of this search, if no volume 113 matching the above condition is found, the process proceeds to S701. If found, one of them is selected, and the process proceeds to S704.

  When the volume 113 corresponding to this condition is found, the volume information 109 and the pair information 109 are updated (S704), and the formation copy is executed (S705). At this time, when the volume information 109 is updated in S704, the pair formation flag 203 of the record of the found secondary volume is rewritten to “pair forming”. Also, a new entry for the pair information 109 is generated, the corresponding volume number is entered in the primary volume number 300 and the secondary volume number 301, the copy pointer is initialized to 0, and the pair status is set to “duplex-pending status”. .

  If the volume 113 corresponding to the above condition is not found, it is checked whether or not the host 100 designates “the primary volume and the secondary volume have the same capacity”, and the next processing to be performed is determined (S701). ). That is, the secondary volume condition 401 of the parameter of the pair creation command received from the host 100 is checked. If the secondary volume condition 401 is “same capacity”, the process proceeds to S703. If the secondary volume condition 401 is not “same capacity”, the process proceeds to S702. I will move on.

  If the secondary volume condition 401 specified by the host 100 is “same capacity”, the corresponding secondary volume does not exist, and this is notified to the host 100 (S703).

  If the secondary volume condition 401 is not “same capacity”, a secondary volume having a capacity larger than the primary volume may be used, and such a volume is searched from the volume information in the control memory 111 (S702). If not found, it is notified to the host 100 (S703).

  If found, the volume information 109 and the pair information 109 are updated (S704), and the formation copy is executed (S705).

  Next, processing of the disk subsystem 101 when the host 100 issues a pair release command to the disk subsystem 101 will be described with reference to FIG.

  When receiving a pair release command from the host 100 via the host interface 102, the control processor 107 of the disk subsystem 101 starts a pair release process 103.

  First, the process to be executed next is determined based on the value of the after-pair cancellation state 502 of the pair cancellation command parameter (S800). When the state 502 after pair cancellation is “secondary volume”, the process proceeds to S802, and when the state 502 after pair cancellation is not “secondary volume”, the process proceeds to S801.

When the status 502 after pair cancellation of the pair cancellation command is “secondary volume”,
Pair information 109 specified by the parameters primary volume number 500 and secondary volume number 501 (the primary volume number 500 and the primary volume number 301 have the same value, and the secondary volume number 501 and the secondary volume number 302 have the same value) Search for pair information 109). Then, the used state of the pair information 109 is canceled by deleting the area of the searched pair information 109. At the same time, “no pair formation” is set in the pair presence / absence flag 203 corresponding to the secondary volume of the volume information 108 (S802). The attribute 202 remains as it is.

  If the state 502 after pair cancellation of the pair cancellation command is not “secondary volume” (that is, “normal volume”), the pair information 109 specified by the parameters primary volume number 500 and secondary volume number 501 is searched. To do. Then, the used state of the pair information 109 is canceled by deleting the area of the searched pair information 109. At the same time, “no pair formation” is set in the pair presence / absence flag 203 corresponding to the secondary volume of the volume information 108, and “normal volume” is set in the attribute 202, and the process ends (S801).

  Next, processing of the disk subsystem 101 when the host 100 issues an attribute change command to the disk subsystem 101 will be described with reference to FIG.

  When receiving a volume attribute change command from the host 100 via the host interface 102, the control processor 107 starts the volume attribute change process 105.

  First, with reference to the pair presence / absence flag 203 of the volume information 108 corresponding to the volume number 600 of the parameter of the attribute change command, it is checked whether or not the volume 113 is “pairing”. If the pair presence / absence flag 203 is “pair forming”, the process proceeds to S901. If the pair presence / absence flag 203 is not “pair forming”, the process proceeds to S902.

  If the pair presence / absence flag 203 is “Pair Formation”, the attribute of the designated volume 113 cannot be changed, so that the host 100 is notified of this, and the process is terminated (S901).

  If the pair presence / absence flag 203 is not “pair formation” (that is, “no pair formation”), the attribute 202 of the volume information 108 is rewritten according to the attribute specified by the attribute 101 after the parameter change of the attribute change command. (S902).

  Finally, the pair status report processing 106 will be described with reference to FIG.

  The host 100 passes the volume number of the primary volume to the disk subsystem 101 as a parameter of the pair status report command.

  When the control processor 107 receives a pair status report command from the host 100 via the host interface 102, the control processor 107 starts the pair status report processing 106.

The control processor 107 refers to all the pair information 109 and searches for the pair information 109 in which the volume number of the primary volume received as a parameter and the primary volume number 301 have the same value. Then, the secondary volume number 302, copy pointer 303, and pair status 304 stored in the searched pair information 109 are reported to the host 100, and the process is terminated (S1000).
(IV) Modified Examples The above is the first embodiment, but some modified examples will be briefly described below.

  In the first embodiment, the condition of the volume 113 as the secondary volume is attached to the parameter of the pair formation command, but this value may not be required. In this case, in the pair formation processing 103, first, an unused secondary volume having the same capacity as that of the volume 113 designated as the primary volume is searched, and if found, a pair is formed with the volume 113, and a volume having the same capacity is found. If not found, an unused secondary volume having a larger capacity is searched for and a pair is formed.

  In the first embodiment, the attribute 202 of the volume 113 is changed by a command from the host 100, but it may be changed from the operation terminal 120 for operating the disk subsystem 1102. In this case, the control processor 107 receives the same command and parameter as the above-described volume attribute change command from the operation terminal 120 via the operation terminal interface 121, and starts the volume attribute change process 105. .

  Further, in the first embodiment, the parameter 202 of the pair release command includes the attribute 202 after releasing the pair of the volume 113 used as the secondary volume, but this value may not be required. In this case, the disk subsystem 101 predetermines how the attribute 202 of the volume 113 used as the secondary volume after the pair is released is always set to “secondary volume” or “normal volume”. Will be.

[Embodiment 2]
Hereinafter, a second embodiment according to the present invention will be described with reference to FIGS.
(I) System Configuration First, the system configuration of the computer system according to the present embodiment will be described with reference to FIG.
FIG. 12 is a block diagram showing a system configuration according to the second embodiment of the present invention.

  In the system of the second embodiment, the configuration of the host and the disk subsystem is the same as in the case of the first embodiment. The difference between this system and the first embodiment is that the system of the first embodiment selects the secondary volume on the side of the disk subsystem, whereas this system uses the disk subsystem. The volume that can be used for the secondary volume is reported from the side, and the host selects it.

  Therefore, the host 1100 executes the secondary volume selection process 1101.

The disk subsystem 1102 is different from the first embodiment in that the pair information is not held in the control memory, the pair status report process is eliminated as the process of the control processor, and the secondary volume report process 1107 is Added. The reason for this configuration is that in this embodiment, the pair status management is performed not on the disk subsystem 1102 side but on the host 1100 side.
(II) Data Structure Next, a data structure used in the system according to the present embodiment will be described with reference to FIG.
FIG. 13 is a schematic diagram illustrating volume information according to the second embodiment.

  The volume information of the second embodiment shown in FIG. 13 is slightly different in configuration from the first embodiment, and is composed of a volume number 1200, an attribute 1201, and a busy flag 1202.

  As in the first embodiment, the volume number 1200 is an identifier for identifying a volume, and the attribute 1201 is set to “normal volume” and “secondary volume”.

The in-use flag 1202 is different from the pair presence / absence flag 203 shown in the first embodiment. The expression is different because of the idea that the disk subsystem 1102 of the second embodiment does not manage pair information. This in-use flag 1202 is a flag indicating whether or not the corresponding volume 113 is used as a secondary volume, and takes one of the values “invalid”, “in use”, or “unused”. When the target volume 113 is “normal volume”, the in-use flag 1202 takes a value of “invalid”. This means that when it has the “normal volume” attribute, it is not assigned as a secondary volume. When the target volume 113 is a “secondary volume” and a pair is formed, the in-use flag 1202 takes a value of “in use”. When the target volume 113 is “secondary volume” and no pair is formed, the in-use flag 1202 takes a value of “unused”.
(III) System Operation Next, the system operation according to the present embodiment will be described with reference to FIGS.
FIG. 14 is a diagram showing a command sequence exchanged between the host 1100 and the disk subsystem 1102 in the second embodiment of the present invention.
FIG. 15 is a flowchart showing processing of the disk subsystem 1102 when a pair formation command is issued in the second embodiment of this invention.
FIG. 16 is a flowchart showing processing of the disk subsystem 1102 when a pair release command is issued in the second embodiment of this invention.
FIG. 17 is a flowchart showing processing of the disk subsystem 1102 when an attribute change command is issued in the second embodiment of this invention.
FIG. 18 is a flowchart showing the secondary volume selection processing of the host 1101 in the second embodiment of the present invention.
FIG. 19 is a flowchart showing the secondary volume report processing of the disk subsystem 1102 when the secondary volume report request command is issued in the second embodiment of this invention.
FIG. 20 is a schematic diagram showing an unused secondary volume list displayed on the host 1100.

  First, a command sequence exchanged between the host 1100 and the disk subsystem 1102 will be described with reference to FIG. 14, and an outline of the operation of the system will be clarified.

  In the second embodiment, when it is necessary to form a pair, the host 1100 needs to know an unused secondary volume number, so a secondary volume report request command is first sent to the disk subsystem 1102. Issue (sq20).

  In response to this, the disk subsystem 1102 reports an unused secondary volume by the secondary volume report (sq21).

  The host 1100 selects one that can be used from the unused secondary volume numbers that have received the report, and holds this. This selection method may be selected by the operator from the screen, or may be automatically selected by a program.

  Then, a pair formation command is issued to the disk subsystem 1102 using the selected secondary volume number as a variable (sq22).

  The subsequent processing is the same as in the first embodiment. That is, a pair status report request command is periodically issued (sq23). When the pair status report request report is “duplex state” (sq24), a pair release command is issued using the held secondary volume number as a parameter (sq25). Further, the trigger for issuing the attribute change command is the same as in the first embodiment (sq30, sq31).

  Next, individual processing of the disk subsystem 1102 and the host 1101 will be described.

  First, the processing of the disk subsystem 1102 when the host 1100 issues a pair formation command to the disk subsystem 1102 will be described with reference to FIG.

  When receiving a pair formation command from the host 1101 via the host interface 102, the control processor 1104 starts a pair formation process 1104.

  The parameters of the issued pair formation command are a primary volume number used as a pair primary volume and a secondary volume number used as a pair secondary volume. This is the same as that of the first embodiment shown in FIG.

  First, the control processor updates the volume information 1108 (S1300). That is, “in use” is set in the in-use flag 1202 of the record corresponding to the secondary volume number received as the parameter of the pair formation command.

  Then, a pair is formed between the primary volume and the secondary volume corresponding to the volume number received as the parameter of the pair formation command, and the formation copy is performed.

  Next, the pair cancellation processing 1105 will be described with reference to FIG.

  When receiving a pair release command from the host 1100 via the host interface 102, the control processor 107 starts a pair release process 1105.

  The issued pair release command includes a primary volume number used as a pair primary volume and a secondary volume number used as a pair secondary volume. This is different from the first embodiment shown in FIG. 5 in that there is no state after pair cancellation 502.

  Upon receiving this command, the control processor sets “unused” to the in-use flag 1202 of the record corresponding to the secondary volume number received as the parameter of the pair release command (S1400).

  Next, processing of the disk subsystem 1102 when the host 1100 issues an attribute change command to the disk subsystem 1102 will be described with reference to FIG.

  When receiving a volume attribute change command from the host 1100 via the host interface 102, the control processor 1106 starts a volume attribute change process 1106.

  The parameters of the volume attribute change command to be issued are the volume number of the volume 113 whose attribute is to be changed and the attribute values after the change (normal volume, secondary volume). This is the same as that of the first embodiment shown in FIG.

  First, the control processor 1106 refers to the parameter of the volume attribute change command and determines whether to change to “normal volume” or “secondary volume” (S1500).

  When changing to “normal volume”, the process proceeds to S1502, and when changing to “secondary volume”, the process proceeds to S1501.

  When changing to “secondary volume”, the volume information 1108 is updated (S1501). That is, “secondary volume” is set in the attribute 1201 corresponding to the volume number of the parameter of the volume attribute change command. When the setting is completed, the volume attribute change process is finished.

  When changing to “normal volume”, it is checked whether or not the designated volume is in use (S1502). This is because the change of the attribute of the volume 113 already used as the secondary volume is rejected. Specifically, the volume information 1108 is referenced to check whether or not the in-use flag 1202 corresponding to the parameter volume number is “in use”.

  If the in-use flag 1202 is “in use”, the attribute cannot be changed, and this is notified to the host 1100 (S1504).

  If the in-use flag 1202 is not “in use”, the volume information 1108 is updated (S1503). That is, “secondary volume” is set in the attribute 1201 corresponding to the volume number of the parameter, and “unused” is set in the in-use flag 1202. When the setting is completed, the volume attribute change processing 1106 is finished.

  In the present embodiment, the basic idea is that the secondary volume is selected on the host 1100 side. The following processing is related to it.

  First, processing for selecting a secondary volume on the host 1100 side will be described with reference to FIG.

  In this embodiment, the host 1100 must determine a secondary volume for storing a data copy when a new pair is formed. Therefore, in order to know which volume 113 can be used as a secondary volume, a secondary volume report request is issued to the disk subsystem 1102 (S1800).

  The disk subsystem 1102 that has received the secondary volume report request notifies the host 1100 of the volume 113 that can be used as a secondary volume, that is, an unused secondary volume number, as a secondary volume report.

  The host 1100 selects a secondary volume number for forming a bear as one secondary volume from among them (S1801). This selection may be displayed as an unused secondary volume number as shown in FIG. 20 on the console of the host 1100 and selected by the operator, or may be automatically selected by a program.

  Next, processing of the disk subsystem 1102 when the host 1100 issues a secondary volume report request command to the disk subsystem 1102 will be described with reference to FIG.

  When the disk subsystem 1102 receives the secondary volume report request command, it references the volume information 1108, edits the volume number of the record in which the in-use flag 1202 is “unused” into a list structure, and 1100 is notified (S1700).

[Embodiment 3]
A third embodiment according to the present invention will be described below with reference to FIGS.

The third embodiment is an improvement of the first embodiment from the viewpoint of secondary volume allocation. In the first embodiment, when the disk sub system selects a secondary volume forming a pair according to a request from the host, the same capacity as the primary volume or a larger capacity is selected. It is good if you can select a secondary volume with the same capacity, but if you select a secondary volume with a larger capacity, the storage area of the volume selected as the secondary volume will not use more than the capacity of the primary volume. As a result, the storage area of the storage device subsystem is wasted. The third embodiment relates to a method of improving this point and creating a volume having the same capacity as the primary volume and using it as a secondary volume.
(I) System Configuration First, the system configuration of the computer system according to the present embodiment will be described with reference to FIG.
FIG. 21 is a block diagram showing a system configuration according to the third embodiment of the present invention.

  Similarly to the system of the first embodiment, the system of this embodiment is configured by the host 100 and the disk subsystem 101. The host interface 102, the control processor 107, and the control memory 111, which are constituent elements of the disk subsystem 101, are substantially the same as those in the first embodiment, but an algorithm of the pair formation processing 1900 that is processing executed by the control processor. Is different from the first embodiment in that the contents of the volume information 1901 in the control memory are different and the unallocated area information 1902 is defined.

  Here, the storage hierarchy model of the present embodiment will be described.

  In the first embodiment, the “volume” has been described using the magnetic disk for managing data as a logical management unit. In this embodiment, it is the same to use the “volume” as the logical management unit, but this volume is further divided and the concept of “logical area” is used as the logical management unit. . Furthermore, a “physical volume” and a “physical area” obtained by further dividing the physical volume are defined as storage unit management units as a more physical concept in the lower layers of these logical concepts. Normally, when managing the storage area in such a layer, the storage management module of the host OS issues a command using the logical storage area, and the storage device or disk subsystem interprets it as a physical area. It is common to access again.

Also in the present embodiment, assuming such a method, when accessing from the volume access mechanism 1904, the access is made as a physical area of the final physical volume. The volume information 1901 has a correspondence between a logical area and a physical area.
(II) Data Structure Next, a data structure used in the system according to the present embodiment will be described with reference to FIGS.
FIG. 22 is a schematic diagram showing volume information according to the third embodiment.
FIG. 23 is a schematic diagram showing unallocated area information.

  The volume information 1901 of the third embodiment includes a volume number 2004, a capacity 201, an attribute 202, a pair presence / absence flag 203, and physical area information 2000. In FIG. 22, only the volume information of one volume number is shown.

  The volume number 1200 is an identifier for identifying a volume, and the roles of the capacity 201, the attribute 202, and the pair presence / absence flag 203 are the same as in the first embodiment.

  What is important in the present embodiment is the physical area information 2000, which is the configuration of the logical area belonging to the logical “volume” having the volume number 2004 and what physical volume number 2002 the logical area has. It indicates whether it corresponds to the physical area of the physical volume.

  In this example, this volume has logical areas with logical area numbers 2001 of 0, 1,..., And the logical area with logical area number 0 is the physical area number 4 in the physical volume with physical volume number 2. It shows that it corresponds to the physical area. That is, when the host 100 issues a command to read data from the area of logical area number 0, the disk subsystem 101 accesses the physical area of physical area number 4 in the physical volume according to the information of the physical area information 2000. The data reading operation is performed from there.

  It is possible to configure the logical area from a plurality of physical areas. However, in this embodiment, for the sake of simplicity, it is assumed that the logical area and the physical area have the same capacity, and one logical area is provided. The description will be made assuming that two physical areas correspond.

A physical area that is not actually used, that is, one that is not allocated to a volume is placed in the unallocated area information 1902 and managed. The unallocated area information 1902 includes a physical volume number 2100 and a physical area number 2101. In the example of this figure, the first entry indicates that the physical area with the physical area number 100 in the physical volume with the physical volume number 10 is not assigned to any volume.
(III) System Operation Next, the operation of the system according to the present embodiment will be described with reference to FIG.
FIG. 24 is a flowchart showing processing of the disk subsystem 101 when a pair formation command is issued in the third embodiment of this invention.

  In the description here, only the pair forming process characteristic of this embodiment will be described.

  When receiving a pair formation command from the host 100 via the host interface 102, the control processor 107 of the disk subsystem 101 starts a pair formation process 103. The pair formation command is the same as that shown in FIG.

  First, the control processor 107 searches for an unused secondary volume with the same capacity as the primary volume (S2200). That is, the capacity 201 of the volume 113 to be the primary volume is calculated from the primary volume number 400 and the volume information 108 of the pair formation command parameters received from the host 100 as in the first embodiment, and then the calculated capacity 201 A volume 113 having a capacity 201 of the same value as in FIG. 5, the attribute 202 is “secondary volume”, and the pair formation presence / absence flag 203 is “no pair formation” is searched for.

  As a result of this search, if no volume 113 matching the above condition is found, the process proceeds to S2201, and if found, one of them is selected, and the process proceeds to S2204.

  When the volume 113 corresponding to this condition is found, the volume information 109 and the pair information 109 are updated as in the first embodiment (S2204), and the formation copy is executed (S2205).

  If no volume corresponding to the above condition is found, the next process to be performed is determined according to the size of the primary volume and the secondary volume (S2201).

  That is, the disk subsystem 1102 refers to the volume information 1902 in FIG. 22 and refers to the volume defined with the attribute 202 as “secondary volume”, the pair presence / absence flag 203 as “no pair formation”, and the capacity 201 as the primary volume. It is checked whether there is a volume 113 having a capacity larger than the capacity 201.

  If there is such a volume 113, go to S2203. If there is no such volume 113, go to S2202.

  When a secondary volume having a capacity larger than the volume defined as the primary volume is not found (S2202), the volume information 1901 is examined, the attribute 202 is “secondary volume”, and the pair presence / absence flag 203 is “no pair formed”. Select an appropriate secondary volume. Next, the difference between the capacity of the selected volume and the volume defined as the primary volume, that is, how much physical area capacity is insufficient is calculated. A physical area corresponding to the capacity of the physical area of the missing area is searched from the unallocated area information 1902, the entry is deleted, and the entry is added to the entry of the physical area information 2000 of the selected secondary volume. As a result, the capacity of the primary volume is equal to the capacity of the volume used as the secondary volume, and copying can be performed.

  When a secondary volume having a capacity larger than the capacity defined as the primary volume is found (S2203), that volume is selected. Next, the difference between the capacity of the selected volume and the volume defined as the primary volume, that is, how much physical area capacity the selected volume has is calculated. Then, in the physical area information 2000 of the selected volume, the physical area entry corresponding to the larger volume is deleted, and the entry is deleted, and the corresponding physical volume number 2100 and physical area 2101 are added to the unallocated area information 1902. To do. That is, an unnecessary area of the selected secondary volume is released. As a result, the capacities of the primary volume and the secondary volume become equal, and the disk area can be effectively used.

  Subsequent volume information and pair information update (S2204) and formation copy execution (S2205) are performed in the same manner in both cases.

It is a block diagram which shows the system configuration | structure which concerns on 1st embodiment of this invention. It is a schematic diagram which shows the volume information of 1st embodiment. It is a schematic diagram which shows pair information. It is a schematic diagram which shows the parameter of a pair formation command. It is a schematic diagram which shows the parameter of a pair cancellation | release command. It is a schematic diagram which shows the parameter of a volume attribute change command. FIG. 3 is a diagram showing a command sequence exchanged between a host 100 and a disk subsystem 101 in the first embodiment of the present invention. 5 is a flowchart showing processing of the disk subsystem 101 when a pair formation command is issued in the first embodiment of the present invention. 5 is a flowchart showing processing of the disk subsystem 101 when a pair release command is issued in the first embodiment of the present invention. 4 is a flowchart showing processing of the disk subsystem 101 when an attribute change command is issued in the first embodiment of the present invention. 4 is a flowchart showing processing of the disk subsystem 101 when a pair status report request command is issued in the first embodiment of the present invention. It is a block diagram which shows the system configuration | structure which concerns on 2nd embodiment of this invention. It is a schematic diagram which shows the volume information of 2nd embodiment. FIG. 10 is a diagram showing a command sequence exchanged between a host 1100 and a disk subsystem 1102 in the second embodiment of the present invention. 10 is a flowchart showing processing of the disk subsystem 1102 when a pair formation command is issued in the second embodiment of the present invention. 12 is a flowchart showing processing of the disk subsystem 1102 when a pair release command is issued in the second embodiment of the present invention. 12 is a flowchart showing processing of the disk subsystem 1102 when an attribute change command is issued in the second embodiment of this invention. 14 is a flowchart showing secondary volume selection processing of the host 1101 in the second embodiment of the present invention. 12 is a flowchart showing a secondary volume report process of the disk subsystem 1102 when a secondary volume report request command is issued in the second embodiment of the present invention. 4 is a schematic diagram showing an unused secondary volume list displayed on a host 1100. FIG. It is a block diagram which shows the system configuration | structure which concerns on 3rd embodiment of this invention. It is a schematic diagram which shows the volume information of 3rd embodiment. It is a schematic diagram which shows unallocated area information. 14 is a flowchart showing processing of the disk subsystem 101 when a pair formation command is issued in the third embodiment of the present invention. It is a figure which shows the outline | summary of a volume replication technique.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Host 101 ... Disk subsystem 102 ... Host interface 103 ... Pair formation process 104 ... Pair release process 105 ... Volume attribute change process 106 ... Pair status report process 107 ... Control processor 108 ... Volume information 109 ... Pair information 111 ... Control memory 112 ... Volume access mechanism 113 ... Volume 1100 ... Host 1101 ... Secondary volume selection processing 1102 ... Disk subsystem 1104 ... Pair creation processing 1105 ... Pair release processing 1106 ... Volume attribute change processing 1107 ... Secondary volume report processing 1108 ... Volume information 1900 ... Pair formation processing 1901 ... Volume information processing 1902 ... Unallocated area information.

Claims (6)

In the storage subsystem connected to the host:
A plurality of volumes to be accessed from the host;
A processor for accessing the plurality of volumes,
When the processor receives an instruction to copy the first volume by designating the first volume as a replication source from the outside,
A storage device subsystem, wherein a second volume for storing a copy is determined based on information on the designated first volume. The storage subsystem of claim 1, comprising:
2. A storage device sub-system according to claim 1, wherein when the replication from the first volume to the second volume is completed, the second volume is released. The storage subsystem of claim 1, comprising:
2. The storage subsystem according to claim 1, wherein when the second volume is selected, a volume larger than the capacity of the first volume designated by the host is selected. The storage subsystem of claim 1, comprising:
When an instruction to change the attribute of whether or not the volume can be a replication destination is received from the outside, the attribute of whether or not the volume can be a replication destination is rewritten to use the volume that is the replication destination A storage subsystem that changes the availability of the storage device. In a host and a computer system connected to the host,
The storage subsystem is
A plurality of volumes set with volume information including an attribute of whether or not the host can be accessed and become a secondary volume;
A memory for storing the volume information;
A processor connected to the memory and accessing the plurality of volumes;
The computer system refers to an attribute indicating whether or not it can become the secondary volume when an external request is made, and reports to the outside a secondary volume that can be used to store a replica. . 6. The computer according to claim 5, wherein a volume for storing a replica is selected from said secondary volumes that can be used to store a copy for which a report has been received, and a copy instruction is given to said storage subsystem. system.

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