JP5293213B2 - Replication volume dynamic generation system and dynamic pair setting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dynamic generation system of a replicated volume for automatically setting a pair relation between a master volume (MV) and a replicated volume (RV) even under the environment in which the number of replicated volumes (RV) of a client site is smaller than the number of master volumes (MV) of a main site, and allowing file access from the client site to the main site using the replication. <P>SOLUTION: When file access is made from the client site 300, the main site 100 automatically sets the pair relation between the master volume (MV) 130 of the main site 100 and the replicated volume (RV) 330 of the client site 300 by a dynamic pair setting means 142, referring to an MV-RV pair management table 145. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a technique called replication in which update data in a master volume at a main site is reflected on a replication volume (RV) at a client site or a subsite via a network line.

One of the load balancing functions of a database management system is replication technology. Replication is a mechanism that reduces the load on communication lines and computers by placing multiple copies of the same content as data stored in a database on a network. The database that holds the master data (master volume) exchanges data with the database that holds the replicated data (replicated volume) through the network, and operates so that the contents always match. In addition, when the data is updated at one place, the update contents are automatically propagated to the master data and all the replicated data.
Here, in replication, the consistency of the replication volume (RV) is not ensured unless all updates of the master volume (MV) are reflected in the replication volume (RV). For this reason, it is not possible to correctly refer to the file of the replication volume (RV) during replication.

  In order to refer to the file on the replication volume (RV), it is either waiting for the completion of replication or using the distributed file system method that maintains the consistency of the file at the main site and the client site. There was a problem.

  The problem with the method of waiting for the completion of replication is that when a large amount of data is updated in the master volume (MV), a long waiting time is required until file access of the replication volume (RV) becomes possible. .

  The problem with the method of using the distributed file system is that the distributed file system operating on both host computers needs to check the update status of the file and transfer the update data. Increase the load).

  Note that there is a SAN disaster recovery system of related technology (see Patent Document 1). However, when an update IO request is issued to the primary disk, the SAN disaster recovery system of Patent Document 1 refers to the pair status table, identifies the secondary disk based on the information, and detects the primary / secondary system. The update IO process is performed on both of them and the synchronization process is executed, and the above-mentioned problems such as the waiting time at the time of replication are not solved.

JP 2006-344090 A

By the way, as a solution to the above-mentioned problems, there are the following methods.
At the client site, in response to a request for access to the file of the replication volume (RV) from the host, the storage at the client site inquires the storage at the main site whether the corresponding area of the replication volume (RV) is the latest. The storage at the main site locks the corresponding area of the master volume (MV) to exclude updates from the main site, transfers the update data of the corresponding area to the client site, and transfers it to the replication volume (RV) at the storage at the client site. By reflecting the update data in the corresponding area, the latest file can be accessed when a request is made at the client site.

However, the following problems remain only with the above solution.
When accessing replicated files from the client site (or subsite), even if the number of volumes to be accessed at the same time is small, it is generally not known which volume is required and when, so the replication volume corresponding to all master volumes (MV) Although it is ideal to prepare (RV), in reality, it is not possible to install a large number of replica volumes (RV).

  Even if it is known when the target master volume (MV) is necessary, it is necessary to manually set and cancel the master volume (MV) / replica volume (RV) pair as needed. For example, in a business mode in which the volume accessed during daytime and nighttime changes, the nighttime replication volume (RV) is unnecessary during the daytime, and the daytime replication volume (RV) is not required during the nighttime. Either daytime and nighttime replication volumes (RV) must be prepared, or the master volume (MV) / replication volume (RV) pair must be changed manually.

  In this way, in an environment where the number of replica volumes (RV) at the client site is smaller than the number of master volumes (MV) at the main site, the pair relationship is switched between the master volume (MV) and the replica volume (RV). It is necessary to replicate necessary data, but manually setting / releasing this pair relationship is a very troublesome task.

  The present invention has been made to solve the above-described problems. The object of the present invention is to establish a pair relationship between a master volume (MV) at a main site and a replica volume (RV) at a client site to replicate data. Even in an environment where the number of replica volumes (RV) at the client site is smaller than the number of master volumes (MV) at the main site, the pair relationship between the master volume (MV) and the replica volume (RV) is manually set. It is an object of the present invention to provide a replication volume dynamic generation system and a dynamic pair setting method, which can automatically set the file and perform file access from the client site to the master volume (MV) of the main site using replication.

  In order to achieve the above object, according to the present invention, a main site having a plurality of master volumes (MV) in a storage unit and a client site having a replication volume (RV) for replicating the contents of the master volume in a storage unit are networked. And a replication volume dynamic generation system in which a pair relationship is set between the master volume (MV) and the replication volume (RV), the master volume (MV) and the client Dynamic replication of a replication volume characterized by comprising dynamic pair setting means for dynamically setting a pair relationship with a replication volume (RV) of a site when file access from a client site to a main site is performed. Generation system.

  Further, the present invention is configured by connecting a main site having a plurality of master volumes (MV) in a storage unit and a client site having a replication volume (RV) for replicating the contents of the master volume in a storage unit via a network. In addition, a dynamic pair setting method in a replication volume dynamic generation system in which a pair relationship is set between the master volume (MV) and the replication volume (RV), wherein the master volume (MV) is set by the main site. Dynamic pair setting characterized in that a dynamic pair setting procedure is performed for dynamically setting a pair relationship between a copy volume and the replication volume (RV) when file access from the client site to the main site is performed. Is the method.

In the replication volume dynamic generation system and the dynamic pair setting method according to the present invention, the main site, when file access is performed from the client site and the subsite, the master volume (MV) / replication volume (RV) Set the pair relationship automatically and dynamically. For example, if there is no pair relationship between the master volume (MV) and the replication volume (RV), a pair relationship is generated and registered.
As a result, even when the number of replica volumes (RV) at the client site and subsite is smaller than the number of master volumes (MV) at the main site, the pair relationship between the master volume (MV) and replica volume (RV) is set manually. Can be set automatically without having to For this reason, file access can be efficiently performed from the host at the client site and the subsite to the master volume (MV) at the main site using replication.

It is a figure which shows the structure of the dynamic generation system of the replication volume which concerns on embodiment of this invention. It is a figure which shows the structural example of a MV * RV pair management table and a reflection difference management table. It is a figure which shows the method (1/4) which accesses the master volume (MV) of the main site from a client site. It is a figure which shows the method (2/4) which accesses the master volume (MV) of the main site from a client site. It is a figure which shows the method (3/4) which accesses the master volume (MV) of the main site from a client site. It is a figure which shows the method (4/4) which accesses the master volume (MV) of the main site from a client site. It is a figure which shows the example when the pair of MV * RV does not exist and there exists unused RV. It is a figure which shows the example when the pair of MV * RV does not exist and an unused RV does not exist. It is a figure which shows the example at the time of adding new RV to a client site. It is a figure which shows the example at the time of adding new MV to the main site. It is a figure which shows the example of the prefetch by access frequency. It is a figure which shows the example (1/8) in case communication with a main site is impossible. It is a figure which shows the example (2/8) in case the communication to a main site is impossible. It is a figure which shows the example (3/8) in case communication with a main site is impossible. It is a figure which shows the example (4/8) in case communication with a main site is impossible. It is a figure which shows the example (5/8) in case communication with a main site is impossible. It is a figure which shows the example (6/8) in case the communication to a main site is impossible. It is a figure which shows the example (7/8) in case the communication to a main site is impossible. It is a figure which shows the example (8/8) in case the communication to a main site is impossible.

[Overview of Dynamic Generation System of Replica Volume of the Present Invention]
A system using a conventional replica volume has the following problems.
The first problem is that, as described above, in an environment where the number of replica volumes (RV) at the client site is smaller than the number of master volumes (MV) at the main site, the master volume (MV) and replica volume (RV) Necessary data must be replicated by switching the pair relationship. Accordingly, the setting / releasing operation of the pair relationship is a very troublesome operation, and it has been desired to solve this problem.

  As a second problem, there are two methods for replication: requesting the client site to request the latest data from the main site, and transferring all data to the client site regardless of the request. is there. The former requires a request for the difference from the latest data from the main site every time there is an access. Therefore, if the access interval to the data is long, the difference with the latest data increases and the transfer data increases. . On the other hand, the latter has a problem that all data must be transferred including data with low access frequency at the subsite.

  As a third problem, if the client site accessing the main site cannot access the master volume (MV) because the network line between the main site and the client site is disconnected, Even if the access is switched to the replication volume (RV) at the site, there is a problem that access is not possible due to file inconsistency unless all updates of the master volume (MV) are reflected in the replication volume (RV) at the subsite.

  The replica volume dynamic generation system of the present invention is configured to solve the above-mentioned problems. The first object of the replica volume dynamic generation system of the present invention is that the number of replica volumes (RV) is the master. Even in an environment where the number of volumes (MV) is smaller, the master volume (MV) and replication volume (RV) pair relationship is automatically set, so that replication can be used from the client site (or subsite) to the main site master. It is to make it possible to efficiently access files on the volume (MV).

  The second object of the dynamic generation system for replica volumes of the present invention is a system for dynamically generating replica volumes, in which the storage at the main site is a fixed area (for example, sector) for access from the client site or subsite. Information on the access frequency, and when the network line usage frequency is low, replication from the main site to the client site and sub-site can be performed in advance based on the access frequency information.

  Furthermore, a third object of the replication volume dynamic generation system of the present invention is that, in the replication volume dynamic generation system, when the network line between the main site and the client site accessing the main site is disconnected, By performing replication using the storage at the subsite connected by another network line as a relay, file access from the client site to the main site can be continued.

  In order to achieve the above object, a replication volume dynamic generation system 1 shown in FIG. 1 is configured. The configuration and operation of the replication volume dynamic generation system of the present invention will be described below.

(Description of the configuration of the dynamic generation system for replication volumes)
A configuration of a replication volume dynamic generation system according to the present invention will be described with reference to FIGS. Here, the outline of the configuration of the replication volume dynamic generation system will be described, and the detailed operation will be described with reference to FIG.

  FIG. 1 is a diagram showing a configuration of a replication volume dynamic generation system according to an embodiment of the present invention. The replication volume dynamic generation system 1 includes a main site 100, a subsite 200, and a plurality of client sites 300.

The main site 100 includes a host computer 110 and a storage (storage unit) 120. The storage 120 includes a plurality of master volumes (MV1, MV2, MV3) and a controller 140.
The subsite 200 includes a host computer 210 and a storage (storage unit) 220, and the storage 220 includes a plurality of replication volumes (RV 1, RV 2, RV 3) 230 and a controller 240.

  The client site 300 includes a host computer 310 and a storage (storage unit) 320, and the storage 320 includes a replication volume (RV) 330 and a controller 340.

  Although FIG. 1 illustrates the case where there are three client sites 300, a larger number of client sites 300 may be arranged. In addition, the master volume (MV) 130 in the main site 100 is exemplified as the master volume MV1, the master volume MV2, and the master volume MV3. However, the present invention is not limited to this, and an arbitrary number of master volumes (MV) can be selected. It can be set as the structure which has.

  In addition, although the three replication volumes RV1, replication volume RV2, and replication volume RV3 are illustrated as the replication volumes (RV) 230 in the subsite 200, the present invention is not limited to this, and an arbitrary number of replication volumes (RV) is provided. 230 can be adopted. Each client site 300 has a configuration having only one replication volume (RV). However, the present invention is not limited to this, and a configuration having an arbitrary number of master volumes (MV) 130 may be used. it can.

  Hereinafter, the configuration of each unit constituting the replication volume dynamic generation system 1 shown in FIG. 1 will be described. The function of each unit and the details of the detailed processing operation will be described in FIG. 3 and subsequent figures, and here, the outline of the configuration will be described.

(Description of client site configuration)
In the client site 300 shown in FIG. 1, the area update unit 313 in the controller 340 performs a file control area and a file data area in the replication volume (RV) 330 in the process of opening a file in response to an instruction from the application (AP) 314. Is sent to the storage 320, and the area lock / transfer means 341 is instructed to update the area of the corresponding replication volume (RV) 330.

  The file system 312 is an interface for the application (AP) 314 on the host 310 to refer to and update the file on the replication volume (RV) 330.

  The replication volume (RV) 330 is a replication destination volume, and is a volume used by the host 310 of the client site 300 and updated by the master volume (MV) 130 of the main site 100 by replication.

The area lock / transfer means 341 in the controller 340 transmits the area information received from the area update means 313 to the main site 100.
Further, when the area lock / transfer unit 341 reflects the data received from the main site 100 in the replication volume (RVn) 330, the replication lock (RVn) 330 is notified in the MV / RV pair management table 145 together with the notification of the reflection completion to the main site 100. 330 requests the update of the access time to 330, raise the reflection flag of the reflection area in the reflection difference management table 146, and update the number of accesses. The area lock / transfer unit 341 includes a unit that releases a reference lock for the master volume (MV) 130 and a communication failure detection unit that detects a network line failure.

  In response to a relay instruction from the site switching unit 343 and the area lock / transfer unit 341 that has detected a communication failure on the network line to the main site 100, a relay request is issued to the site switching management unit 247 of the subsite 200, and whether or not the request is accepted. Receive notifications. Further, upon receiving a notification at the time of communication restoration, it requests the site switching management means 247 to end the relay processing.

(Description of main site configuration)
A master volume (MV) 130 in the main site 100 is a replication source volume and is a volume used by the host of the main site 100. When the master volume (MV) is updated, the update location in the volume is recorded in the reflection difference management table 146. The replication volume (RV) is a replication destination volume, and is a volume used by the hosts of the client site 300 and the subsite 200, and data updated in the master volume (MV) is written by replication.

  The MV / RV pair management table 145 is a management table for registering a pair having a relationship in which replication is performed between a master volume (MV) and a replication volume (RVn). It has the latest access time to the replication volume (RV) 330 at the client site 300 and the replication volume (RV) 230 at the subsite 200 and a link to the reflection difference management table 146.

  The reflection difference management table 146 reflects the data of the master volume (MV) in the replication volumes (RV) 230 and 330 for each predetermined area (for example, sector) of the data accessed from the client site 300 and the subsite 200. It is a management table that manages whether the access is made and the access frequency of the corresponding area.

  The file control area 131 in the master volume (MV) 130 is an area in which file control information is stored, and has file area information. The file data area 132 is an area in which file data is stored.

  The area lock / transfer means 141 in the controller 140 instructs the dynamic pair setting means 142 to return the presence / absence of a difference in the corresponding area after performing the reference lock of the designated area of the master volume (MV) 130. If there is a difference, the difference is transferred to the client site 300 and the subsite 200. If it has been reflected, this is notified to the client site 300 and the subsite 200.

  The dynamic pair setting unit 142 of the main site 100 confirms whether or not the master volume (MV) 130 designated by the area lock / transfer unit 141 exists in the MV / RV pair management table 145. It is confirmed from the table 146 whether the update of the designated area is reflected in the replication volume (RV) 330 of the client site 300, and the result is returned to the area lock / transfer unit 141.

  The dynamic pair setting unit 142 searches for an unused replication volume (RV) when there is no replication volume (RV) corresponding to the master volume (MV) in the MV / RV pair management table 145. When an unused replication volume (RV) exists, the replication volume (RV) is registered in the MV / RV pair management table 145 as a master volume (MV) pair.

  The dynamic pair setting unit 142 also updates the replication volume (RV) access time from the client site 300 and the sub-site 200 and the update request for the reflected area raising access count of the reflection area. 145 and the reflection difference management table 146 are updated.

  In addition, the prefetching unit 143 uses the prefetching area indexing unit (prefetching area indexing unit) 144 to identify an area in which the master volume (MV) 130 area is unreflected from the reflection difference management table 146 and has a high access frequency. Search, determine the replication volume (RV) 330 of the corresponding area from the MV / RV pair management table 145, and instruct the area lock / transfer means 141 to transfer the difference data of the area to the replication volume (RV) 330. .

(Description of subsite structure)
The subsite 200 is provided for relaying between the main site 100 and the client site 300 when the network connecting the main site 100 and the client site 300 becomes unable to communicate. For this reason, the subsite 200 has the same components as the main site 100.

  The area lock / transfer means 241 in the controller 240 of the subsite 200 writes the data received from the main site 100 to the replication volume (RV) 230 at the time of replication, and the received data from the main site 100 to the replication volume (RV). 230, after the reflection is notified to the main site 100, update of the replication volume (RV) access time in the MV / RV pair management table 145, and raising the reflection flag of the reflection area in the reflection difference management table 146 Request update of access count.

  The area lock / transfer unit 241 reflects the data of the replication volume (RV) 230 in the replication volume (RV) 330 of the client site 300 when accessed from the client site 300.

  The dynamic pair setting unit 242 confirms whether or not the replication volume (RV) 330 designated by the area lock / transfer unit 241 exists in the MV / RV pair management table 245 and, if present, from the reflection difference management table 246. It is confirmed whether the update of the designated area is reflected in the replication volume (RV) 330 of the client site 300, and the result is returned to the area lock / transfer means 241.

  When the site switching management unit 247 receives a relay request from the site switching unit 343 of the client site 300 and there is a volume that has already been replicated with respect to the requested volume, the site switching management unit 247 and the MV / RV pair management table 145 and the reflection difference Information on the client site 300 that has received the request is requested from the management table 146. Then, the request is copied to the MV / RV pair management table 245 and the reflection difference management table 246 in the subsite 200, and the request acceptance is notified to the site switching means 343 of the client site 300. On the other hand, if there is no volume that has already been replicated, a new volume is allocated, the volume is added to the main site 100 as a replication volume (RV), and added to the MV / RV pair management table 145. MV) to the MV / RV pair management table 245 and notify the site switching means 343 of the client site 300 of request acceptance.

  The MV / RV pair management table 245 is a management table for registering a pair having a relationship in which replication is performed between a master volume (MV) and a replication volume (RV). Also, the latest time when the replication volume (RV) 230 was accessed and a link to the reflection difference management table 246 are provided.

  The file control area 231 of the replication volume (RV) 230 is an area in which file control information is stored, and has file area information. The file data area 232 is an area where file data is stored.

  FIG. 2 is a diagram illustrating a configuration example of the MV / RV pair management table and the reflection difference management table described above. The MV / RV pair management table shown in FIG. 2 is used to manage whether there is a pair relationship between the master volume (MV) at the main site and the replication volume (RV) at the client site (or) subsite. .

  In the MV / RV pair management table shown in FIG. 2, the master volume (MV1) and the replication volume (RV1) are in a pair state, the master volume (MV2) is not paired, and the replication volume (RV2) Is not paired. In addition, in the master volume (MV1) and the replication volume (RV1) in the pair state, the access time t1 from the replication volume (RV1) is recorded, and the reflection difference from the master volume (MV1) to the replication volume (RV1) Link information to the management table is recorded.

  The reflection difference management table is used to determine whether the corresponding area in the master volume (MV) is reflected in the replication volume (RV) using the reflection difference management table when a file is accessed from another site. It is. In this reflection difference management table, information on whether or not the update of the master volume (MV) has been reflected and information on the number of accesses are recorded for each area (sector).

The operation of the first embodiment will be described with reference to FIGS.
FIGS. 3 to 6 are diagrams for explaining the cooperative operation between the storage 120 and 320 of the main site 100 / client site 300 when a file is input and opened from the application (AP) 314 at the client site 300. FIG. The processing flow will be described below with reference to FIGS.

  Referring to FIG. 3, an application (AP) 314 on the host 310 of the client site 300 requests the file system 312 to open a file existing in the main site 100 (step S101).

  The area update unit 313 in the file system 312 updates the area in which the file control area 331 in the replication volume (RV) 330 is arranged with respect to the area lock / transfer unit 341 in the controller 340 of the storage 320. Is instructed (step S102).

  The area lock / transfer unit 341 of the storage 320 requests the main site 100 to obtain a reference lock in the area where the file control area 331 is arranged and to transfer the latest data (step S103).

  The area lock / transfer means 141 in the controller 140 of the main site 100 performs reference lock on the area where the file control area 131 in the master volume (MV) 130 is arranged from the request information from the client site 300 (step S104). ).

  The dynamic pair setting unit 142 in the controller 140 of the main site 100 obtains a link from the request information to the reflection difference management table 146 corresponding to the replication volume (RV) 330 of the corresponding volume from the MV / RV pair management table 145. (Step S105).

  Next, referring to FIG. 4, the dynamic pair setting unit 142 of the main site 100 refers to the reflection difference management table 146 based on the acquired link, and the update of the file control area 131 is updated to the replication volume (RV) 330. The area lock / transfer means 141 is notified (step S106).

  The area lock / transfer unit 141 of the main site 100 does not reflect the update of the file control area 131 on the replication volume (RV) 330 of the client site 300 based on the information notified from the dynamic pair setting unit 142. If the difference is obtained from the file data area 132 of the master volume (MV) 130 and transferred to the client site 300, or if the update of the file control area 131 is reflected in the replication volume (RV) 330, This is notified to the client site 300 (step S107).

  The area lock / transfer unit 341 of the client site 300 writes the received data to the replication volume (RV) 330 (step S108).

  Subsequently, the area lock / transfer unit 341 updates the replication volume (RV) access time in the MV / RV pair management table 145 and the corresponding area in the reflection difference management table 146 to the dynamic pair setting unit 142 of the main site 100. The dynamic pair setting unit 142 of the main site 100 updates the MV / RV pair management table 145 and the reflection difference management table 146 according to the request (step S109). ).

  The area lock / transfer means 341 of the client site 300 notifies the area update means 313 of the host 310 of the completion of the update of the file control area 331 (step S110). The area updating unit 313 acquires area information where the file data area 332 is arranged from the updated file control area 331 (step S111).

  Next, referring to FIG. 5, the area update unit 313 instructs the area lock / transfer unit 341 of the storage 320 to update the area where the file data area 332 is arranged (step S112).

The area lock / transfer unit 341 of the client site 300 requests the main site 100 to acquire the reference lock of the area where the file data area 332 is arranged, release the reference lock of the file control area, and transfer the latest data (step S113). ).
The area lock / transfer means 141 of the main site 100 performs a reference lock on the area where the file data area 132 is arranged from the request information, and releases the reference lock of the file control area 131 (step S114).

  The dynamic pair setting unit 142 acquires a link from the request information to the reflection difference management table 146 corresponding to the replication volume (RV) 330 of the corresponding volume from the MV / RV pair management table 145 (step S115).

  The dynamic pair setting unit 142 refers to the reflection difference management table 146 based on the acquired link, confirms whether the update of the file data area is reflected in the replication volume (RV) 330, and locks and transfers the area. 141 is notified (step S116).

  Subsequently, referring to FIG. 6, the area lock / transfer unit 141 of the main site 100 updates the file data area 132 based on the information notified from the dynamic pair setting unit 142 and updates the replication volume (RV) 330. If the difference is not reflected in the master volume (MV) 130, the difference is acquired from the master volume (MV) 130 and transferred to the client site 300, or if the update of the file data area 132 is reflected in the replication volume (RV) 330, This is notified to the client site 300 (step S117).

The area lock / transfer unit 341 of the client site 300 writes the received data to the replication volume (RV) 330 (step S118).
Subsequently, the area lock / transfer unit 341 updates the replication volume (RV) access time in the MV / RV pair management table 145 and the corresponding in the reflection difference management table 146 with respect to the dynamic pair setting unit 142 of the main site 100. The dynamic pair setting unit 142 of the main site 100 updates the MV / RV pair management table 145 and the reflection difference management table 146 in accordance with the request, raising the reflected flag of the area to be updated and updating the access count ( Step S119).

The area lock / transfer unit 341 of the client site 300 requests the main site 100 to release the reference lock of the file data area 132 (step S120). The area lock / transfer unit 141 of the main site 100 releases the reference lock of the file data area 132 (step S121).
The area lock / transfer unit 341 of the client site 300 notifies the host area update unit 313 of the completion of the update of the file data area 332 (step S122). The area updating means 313 notifies the application (AP) 314 that the file opening has been completed through the file system 312 (step S123).

  As described above, the contents of the master volume (MV) 130 in the main site 100 and the contents of the replication volume (RV) 330 in the client site 300 match according to the procedure shown in FIGS. After confirmation, the file in the replication volume (RV) 330 is opened to the application (AP) 314.

  FIG. 7 illustrates a case where there is no master volume (MV) / replication volume (RV) pair and there is an unused replication volume (RV). In FIG. 7, the same processing is performed in steps S101 to S105 in FIG. 3, and in steps S107 to S123 in FIGS. 4, 5, and 6, and step S106 in FIG. 4 is changed to the following processing.

  Referring to FIG. 7, when the dynamic pair setting unit 142 refers to the MV / RV pair management table 145, and there is no replication volume (RV) corresponding to the master volume (MV) 130, the dynamic pair setting unit 142 An unused replication volume (RV) is searched from the management table 145, a master volume (MV) / replication volume (RV) pair is generated, and registered in the MV / RV pair management table 145. Then, a link to the reflection difference management table 146 corresponding to the replication volume (RV) is acquired from the MV / RV pair management table 145 (step S106a).

  Subsequently, the dynamic pair setting unit 142 determines the reflection difference management table 146 based on the acquired link, and initializes the master volume (MV) data to a state where it is not reflected in the replication volume (RV). Then, with reference to the reflection difference management table 146, it is confirmed whether the update of the file control area is reflected in the replication volume (RV), and notifies the area lock / transfer means 341 (step S106b).

  FIG. 8 illustrates a case where there is no master volume (MV) / replication volume (RV) pair and there is no unused replication volume (RV). In FIG. 8, the same processing is performed in steps S101 to S105 in FIG. 3 described above, and in steps S107 to S123 in FIGS. 4, 5, and 6, and step S106 in FIG. 4 is changed to the following processing. .

  Referring to FIG. 8, when the dynamic pair setting unit 142 refers to the MV / RV pair management table 145, there is no replication volume (RV) corresponding to the master volume (MV), and an unused replication volume ( If there is no RV), the master volume (MV) / replica volume (RV) pair that is unlikely to be accessed from the client site 300 is deleted from the MV / RV pair management table 145 and released from the requested master volume (MV). A master volume (MV) / replica volume (RV) pair is generated with the replicated volume (RV) and registered in the MV / RV pair management table 145. Then, a link to the reflection difference management table 146 corresponding to the replication volume (RV) is acquired from the MV / RV pair management table 145 (step S106a).

  Subsequently, the dynamic pair setting unit 142 determines the reflection difference management table 146 based on the acquired link, and initializes the master volume (MV) data to a state where it is not reflected in the replication volume (RV). Then, with reference to the reflection difference management table 146, it is confirmed whether the update of the file control area is reflected in the replication volume (RV), and notifies the area lock / transfer means 341 (step S106b).

  FIG. 9 is a diagram for explaining a case where a new replication volume (RV) is added to the client site 300. A dynamic pair setting unit 345 is added to the controller 340 in the client site 300 shown in FIG.

  Referring to FIG. 9, first, a new replication volume (RV2) 330a is added to the storage 320 at the client site 300 (step S201).

  Next, the dynamic pair setting unit 345 of the client site 300 notifies the main site 100 of the newly added replication volume (RV2) 300a (step S202).

  The dynamic pair setting unit 142 of the main site 100 registers the notified replication volume (RV2) 300a in the MV / RV pair management table 145 (step S203).

FIG. 10 illustrates a case where a new master volume (MV) is added to the main site 100.
Referring to FIG. 10, first, a new master volume (MV2) 130a is added to the storage 120 of the main site 100 (step S301).

  Next, the dynamic pair setting unit 142 of the main site 100 registers the newly added master volume (MV2) 130a in the MV / RV pair management table 145 (step S302).

  As described above, in the replication volume dynamic generation system of the present invention, when file access is performed from the client site 300 to the master volume (MV) 130 of the main site, the area lock / transfer means 141 of the main site 100 and The area lock / transfer unit 341 at the client site 300 performs reference lock on the master volume (MV) 130 and transfer of the latest data to the client site 300.

  In this case, the dynamic pair setting unit 142 of the main site 100 dynamically sets the pair relationship between the master volume (MV) 130 and the replication volume (RV) 330. For example, when there is no replication volume (RV) corresponding to the master volume (MV) 130, an unused replication volume (RV) is searched from the MV / RV pair management table 145, and the master volume (MV) / replication volume (RV) is searched. A pair is generated and registered in the MV / RV pair management table 145. If there is no unused replication volume (RV), the master volume (MV) / replication volume (RV) pair that is unlikely to be accessed from the client site 300 is deleted from the MV / RV pair management table 145 and requested. A pair relationship is generated between the released master volume (MV) and the released replica volume (RV) and registered in the MV / RV pair management table 145.

  As a result, even when there is no pair relationship between the master volume (MV) 130 and the replication volume (RV) 330, this pair relationship can be set dynamically and the latest data can be transmitted to the client site 300.

Although the first embodiment has been described above, the replication volume dynamic generation system 1 determines the pair relationship between the master volume (MV) 130 and the replication volume (RV) 130 at the client site from the client site to the main site. It has dynamic pair setting means 142 that dynamically sets when file access is performed.
As a result, even when there is no pair relationship between the master volume (MV) 130 and the replication volume (RV) 330 at the client site 300, this pair relationship is dynamically set and the latest data is transmitted to the client site 300. be able to.

Further, the replication volume dynamic generation system 1 further includes a subsite 200, and the pair relationship between the master volume (MV) 130 and the replication volume (RV) 230 of the subsite 200 is transferred from the subsite 200 to the main site 100. When the file access is performed, a dynamic pair setting unit 142 that dynamically sets the file is provided.
Thus, even when there is no pair relationship between the master volume (MV) 130 and the replication volume (RV) 230 of the subsite 200, this pair relationship is dynamically set and the latest data is transmitted to the subsite 200. be able to.

  Next, as a second embodiment of the present invention, an example of performing replication from the main site to the client site and the subsite in advance will be described.

  As described above, replication includes a method of requesting the latest data from the main site after a request from the client site, and a method of transferring all data to the client site regardless of the request. The former requires a request for the difference from the latest data from the main site every time there is an access, so if the access interval to the data is long, the difference with the latest data will increase and the transfer data will increase. On the other hand, the latter has a problem that all data must be transferred including data with low access frequency at the subsite.

  In the second embodiment of the present invention, when the main site has access frequency information for each area (for example, sector) and access from the client site or subsite is low, and the network line usage frequency is low, Based on the access frequency information, replication from the main site to the client site and subsite can be performed in advance.

The processing operation of the second embodiment of the present invention will be described below.
FIG. 11 is a diagram for explaining prefetching based on access frequency. Hereinafter, the flow of the process will be described with reference to FIG.

  The prefetching means 143 of the main site 100 uses the prefetching area indexing means 144 to refer to the reflection difference management table 146 and find an area where the update of the master volume (MV) 130 is not reflected and which has a high access count. Determine (step S401).

The prefetching means 143 of the main site 100 refers to the MV / RV pair management table 145, acquires the replication volume (RV) of the determined area, and instructs the area lock / transfer means 141 to transfer the corresponding area (step S402). ).
The area lock / transfer means 141 of the main site 100 acquires the corresponding area data from the master volume (MV) 130 (step S403).

The area lock / transfer unit 141 of the main site 100 transfers the acquired area data to the client site 300 (step S404).
The area lock / transfer unit 341 of the client site 300 writes the data received from the main site 100 to the replication volume (RV) 330 (step S405).
The area lock / transfer unit 341 of the client site 300 notifies that the data of the area corresponding to the main site 100 is reflected in the replication volume (RV) 330 (step S406).

  The area lock / transfer unit 141 of the main site 100 notifies the dynamic pair setting unit 142 that the reflection of the replication volume (RV) 330 has been completed for the corresponding area, and the dynamic pair setting unit 142 sets the reflection difference management table 146. The corresponding area is updated as having been reflected in the difference (step S407).

  As a result, when the frequency of use of the network line is low, replication can be performed in advance from the main site to the client site and subsite based on the access frequency information.

The second embodiment has been described above. In the second embodiment, the main site 100 is described in the MV / RV pair management table 145 and the MV / RV pair management table 145 describing the pair relationship. A reflection difference management table 146 that is associated with a pair relationship and stores the access frequency of an area accessed by file access to the master volume (MV) 130, and the reflection difference management table 146 stores each master volume (MV) 130. A pre-reading area indexing unit 144 for determining an area having a high access frequency, and a client having a pair relationship with data having a high access frequency in advance based on the access frequency information read using the pre-reading area indexing unit 144 A pre-reading means 143 for transmitting to the site 300 and the sub-site 200. The region in the master volume (MV) 130 which processes the frequency is determined to be high, and transmits the data to be transmitted in the area when the space on the network line, the client sites 300, and the sub-site 200.
As a result, when the frequency of use of the network line is low, replication can be performed in advance from the main site to the client site and subsite based on the access frequency information.

    Next, an example in which the network line between the main site and the client site accessing the main site is disconnected will be described as a third embodiment of the present invention.

  As described above, if the client site accessing the main site cannot access the master volume (MV) due to the disconnection of the network line between the main site and the client site, the replication volume of the subsite Even if the access is switched to (RV), there is a problem that access is not possible due to file inconsistency unless all updates of the master volume (MV) are reflected in the replication volume (RV).

  Therefore, in the third embodiment, when the network line between the main site 100 and the client site 300 accessing the main site is disconnected, the storage at the subsite 200 is used as a relay to the main site 100 as it is. This is an example in the case where file access is continuously performed.

The processing operation in the third embodiment will be described below.
12 to 19 are diagrams for explaining the processing operation in the third embodiment, and the flow of the processing will be described below with reference to FIGS. 12 to 19.

    Referring to FIG. 12, application (AP) 314 on the host of client site 300 requests file system 312 to open a file existing in main site 100 (step S501).

  The area update unit 313 of the file system 312 instructs the area lock / transfer unit 341 of the storage 320 to update the area where the file control area is arranged (step S502).

The area lock / transfer means 341 in the storage 320 requests the main site 100 to update the area where the file control area is arranged, but recognizes that the communication failure detection means 342 cannot communicate, The switching unit 343 is instructed to request relay to another site (step S503).
The site switching unit 343 requests the subsite 200 to relay to the main site 100 (step S504).

  The site switching management means 247 of the sub-site 200 sends the information of the client site 300 that has received the request to the main site 100 (master volume (MV) paired from the MV / RV pair management table 145 and its master volume ( Information is acquired from the reflection difference management table 146) of MV) (step S505).

The site switching management unit 247 performs the following processing on the acquired information on the client site 300.
For the master volume (MV) 130 paired with the replication volume (RV) 330 at the client site 300, the replication volume (RV) 230 paired with the same master volume (MV) 130 at the subsite 200 is determined. The determined replication volume (RV) 230 of the subsite 200 is used as a master volume (MV) to create a pair with the replication volume (RV) 330 of the client site 300 and register it in the MV / RV pair management table 245. Subsequently, the acquired reflection difference table is registered in the MV / RV pair management table 245 (step S506).

  The site switching management unit 247 of the sub-site 200 notifies the client site 300 that the relay request has been accepted (step S507).

  Subsequently, referring to FIG. 13, the area lock / transfer unit 341 of the client site 300 requests the subsite 200 to update the area where the file control area of the main site 100 is arranged (step S508). ).

The area lock / transfer unit 241 of the sub-site 200 recognizes the request received from the client site 300 as a request to the main site 100, and instructs the site switching management unit 247 to return the site information for transferring the request (step S509). .
The area lock / transfer unit 241 of the subsite 200 requests the main site 100 to acquire a reference lock in the file control area and transfer the latest data based on the site information to be transferred obtained from the site switching management unit 247. (Step S510).

  A series of operations from step S511 in FIG. 13 to step S518 in FIG. 14 is the same as the above-described operation from step S104 in FIG. 3 to step S109 in FIG. 4 except that the client site 300 is replaced with the subsite 200. is there.

  That is, the area lock / transfer unit 141 in the controller 140 of the main site 100 performs reference lock on the area where the file control area in the master volume (MV) 130 is arranged from the request information (step S511).

  The dynamic pair setting unit 142 in the controller 140 of the main site 100 acquires a link from the request information to the reflection difference management table 146 corresponding to the replication volume (RV) of the corresponding volume from the MV / RV pair management table 145. (Step S512).

  The dynamic pair setting unit 142 of the main site 100 refers to the reflection difference management table 146 based on the acquired link, confirms whether the update of the file control area 131 is reflected in the replication volume (RV) 330, and The lock / transfer means 141 is notified (step S513).

  Subsequently, referring to FIG. 14, the area lock / transfer means 141 of the main site 100 updates the file control area 131 based on the information notified from the dynamic pair setting means 142 (step S514). If not reflected in the replication volume (RV) 230 of the site 200, the difference is acquired from the file data area 132 of the master volume (MV) 130 (step S515) and transferred to the subsite 200 (step S516), or If the update of the file control area 131 is reflected in the replication volume (RV) 230, the fact is notified to the subsite 200.

  The area lock / transfer unit 241 of the subsite 200 writes the received data to the replication volume (RV) 230 (step S517).

  Subsequently, the area lock / transfer unit 241 updates the replication volume (RV) access time in the MV / RV pair management table 145 and the corresponding area in the reflection difference management table 146 to the dynamic pair setting unit 142 of the main site 100. The dynamic pair setting unit 142 of the main site 100 updates the MV / RV pair management table 145 and the reflection difference management table 146 according to the request (step S518). ).

  In order to respond to the client site 300, the area lock / transfer unit 241 of the subsite 200 returns information on the site to which the response of the request is transferred and the replication volume (RV) of the site to the site switching management unit 247 ( (Send) is instructed (step S519).

  A series of operations from step S520 in FIG. 14 to step S530 in FIG. 16 to be described below is the same as the operation from step S105 in FIG. 3 to step S113 in FIG. 3 described above, except that the main site 100 is replaced with the subsite 200. The same.

  That is, in FIG. 14, the dynamic pair setting unit 242 uses the relay replication volume (RV) 230 as the master volume (MV), generates a pair with the newly registered replication volume (RV), and generates MV · RV Registration is made in the pair management table 245 (step S520). The dynamic pair setting unit 242 registers the reflection difference management table 246 in the MV / RV pair management table 245 (step S521).

  Next, referring to FIG. 15, the dynamic pair setting unit 242 refers to the reflection difference management table 246, and whether the update of the file control area 231 is reflected in the replication volume (RV) 330 of the client site 300. And notifies the area lock / transfer means 241 (step S522).

  If the update of the file control area 231 is not reflected in the replication volume (RV) 330 of the client site 300 based on the information notified from the dynamic pair setting means 242, the area lock / transfer means 241 The difference is acquired from the file control area 231 of the replication volume (RV) 230 (step S523) and transferred to the client site 300 (step S524), or the update of the file control area 231 is reflected in the replication volume (RV) 230. If so, the client site 300 is notified accordingly.

  The area lock / transfer unit 341 of the client site 300 writes the received data to the replication volume (RV) 330 (step S525).

  Subsequently, the area lock / transfer unit 341 of the client site 300 updates the replication volume (RV) access time in the MV / RV pair management table 245 and the reflection difference management table to the dynamic pair setting unit 242 of the subsite 200. The dynamic pair setting unit 242 of the subsite 200 requests to raise the reflected flag of the corresponding area in 246 and update the access count, and the MV / RV pair management table 245 and the reflection difference management table 246 according to the request. Is updated (step S526).

  The area lock / transfer means 341 of the client site 300 notifies the area update means 313 of the host 310 of the completion of the update of the file control area 331 (step S527).

Subsequently, with reference to FIG. 16, the area update unit 313 acquires area information in which the file data area 332 is arranged from the updated file control area 331 (step S528).
The area update unit 313 instructs the area lock / transfer unit 341 of the storage 320 to update the area in which the file data area is arranged (step S529).
The area lock / transfer unit 341 of the client site 300 requests the subsite 200 to acquire the reference lock of the area where the file data area is arranged, release the reference lock of the file control area, and transfer the latest data (step S530). ).

  The area lock / transfer unit 241 of the sub-site 200 recognizes the request received from the client site 300 as a request to the main site 100, and instructs the site switching management unit 247 to return information on the site to which the request is transferred (step S531). ).

  A series of processing operations from step S532 in FIG. 16 to step S540 in FIG. 17 described below is the same as the operation from step S113 in FIG. 5 to step S119 in FIG. This is the same except that is replaced with.

That is, in FIG. 16, the area lock / transfer means 341 of the subsite 200 acquires the reference lock of the area where the file data area is arranged with respect to the main site 100, releases the reference lock of the file control area, and transfers the latest data. A request is made (step S532).
The area lock / transfer means 141 of the main site 100 performs a reference lock on the area where the file data area 132 is arranged from the request information, and releases the reference lock of the file control area 131 (step S533).

  The dynamic pair setting unit 142 acquires a link from the request information to the reflection difference management table 146 corresponding to the replication volume (RV) of the corresponding volume from the MV / RV pair management table 145 (step S534).

  The dynamic pair setting unit 142 refers to the presence / absence of a difference between the corresponding areas (step S535). That is, the dynamic pair setting unit 142 refers to the reflection difference management table 146 based on the acquired link.

  Next, referring to FIG. 17, the dynamic pair setting unit 142 confirms whether the update of the file control area 131 is reflected in the replication volume (RV) 230 of the subsite 200, and the area lock / transfer unit 141. (Step S536).

  If the update of the file data area 132 is not reflected in the replication volume (RV) 230 of the subsite 200 based on the information notified from the dynamic pair setting unit 142, the area lock / transfer unit 141 calculates the difference Is acquired from the master volume (MV) (step S537) and transferred to the subsite 200 (step S538). Alternatively, if the update of the file data area 132 is reflected in the replication volume (RV), the fact is notified to the subsite 200.

  The area lock / transfer unit 241 of the subsite 200 writes the received data to the replication volume (RV) 220 (step S539).

  Subsequently, the area lock / transfer unit 241 updates the replication volume (RV) access time in the MV / RV pair management table 145 and the corresponding in the reflection difference management table 146 with respect to the dynamic pair setting unit 142 of the main site 100. The dynamic pair setting unit 142 of the main site 100 updates the MV / RV pair management table 145 and the reflection difference management table 146 in accordance with the request, raising the reflected flag of the area to be updated and updating the access count ( Step S541).

  In order to respond to the client site 300, the area lock / transfer unit 241 of the subsite 200 returns the request transfer response to the site switching management unit 247 and information on the replication volume (RV) of the site. An instruction is given (step S541).

  In the following description, the series of operations from step S542 in FIG. 17 to step S548 in FIG. 18 is the same as the operation from step S115 in FIG. 5 to step S119 in FIG. It is the same except for replacing.

  In other words, in FIG. 17, the dynamic pair setting unit 242 acquires a link from the request information to the reflection volume management table 246 corresponding to the replication volume (RV) 230 of the corresponding volume from the MV / RV pair management table 245 ( Step S542).

  The dynamic pair setting unit 242 refers to the presence / absence of a difference between the corresponding areas (step S543). That is, referring to the reflection difference management table 246 based on the acquired link, it is confirmed whether the update of the file control area is reflected in the replication volume (RV) 330 of the client site 300.

  Next, with reference to FIG. 18, the dynamic pair setting unit 242 refers to the presence / absence of a difference in the corresponding region, and notifies the region lock / transfer unit 241 of the presence / absence of the difference in the corresponding region (step S544). .

  If the update of the file data area 232 is not reflected in the replication volume (RV) 330 of the client site 300 based on the information notified from the dynamic pair setting means 242, the area lock / transfer means 241 Is acquired from the replication volume (RV) 230 in the subsite 200 (step S545) and transferred to the client site 300 (step S546). Alternatively, if the update of the file data area 132 is reflected in the replication volume (RV) 330, the client site 300 is notified of this.

The area lock / transfer unit 341 of the client site 300 writes the received data to the replication volume (RV) 330 (step S547).
Subsequently, the area lock / transfer unit 341 of the client site 300 updates the replication volume (RV) access time in the MV / RV pair management table 245 and the reflection difference with respect to the dynamic pair setting unit 242 of the subsite 200. A request is made to raise the reflected flag of the corresponding area in the management table 246 and update the access count (step S548), and the dynamic pair setting unit 242 of the subsite 200 responds to the request by the MV / RV pair management table 245 And the reflection difference management table 246 is updated.

  Subsequently, referring to FIG. 19, the area lock / transfer means 341 of the client site 300 requests the subsite 200 to release the reference lock of the area where the file data area of the main site 100 is arranged (step). S549).

The area lock / transfer unit 241 of the subsite 200 recognizes the request received from the client site 300 as a request to the main site 100, and instructs the site switching management unit 247 to return the site information to which the request is transferred (step S550). .
The area lock / transfer unit 241 of the subsite 200 requests the main site 100 to release the reference lock of the file data area based on the site information to be transferred obtained from the site switching management unit 247 (step S551).

The area lock / transfer unit 141 of the main site 100 releases the reference lock of the file data area 132 (step S552).
The area lock / transfer unit 341 of the client site 300 notifies the host area update unit 313 of the completion of the update of the file data area 332 (step S553).
The area updating unit 313 notifies the application (AP) 314 that the file opening has been completed through the file system 312 (step S554).

  As a result, when the network line between the main site and the client site accessing the main site is interrupted, the file on the main site is replicated using the storage of the subsite connected by another network line as a relay. Can continue to access.

As described above, in the third embodiment, the replication volume dynamic generation system 1 is connected to the main site 100 via the communication network, and the contents of the master volume (MV) 130 of the main site 100 are stored. A subsite 200 having a replication volume (RV) 230 to be replicated in a storage unit is provided.
When the client site 300 detects that the network line between the client site 300 and the main site 100 is disconnected, and the communication failure detecting unit 342 detects that the network line is disconnected. And site switching means 343 for switching the access destination to the sub-site 200.
Further, the subsite 200 receives a switching request from the site switching unit 343 of the client site 300, and acquires a site switching management unit 247 that acquires information for relaying between the main site 100 and the client site 100, and a master of the main site 100. And area lock / transfer means for relaying replication between the volume (MV) 130 and the replication volume (RV) 330 at the client site 300.
Upon receiving notification that the communication network line between the client site 300 and the main site 100 is disconnected, the subsite 200 receives the master volume (MV) 130 of the main site 100 and the replication volume (RV) 330 of the client site 300. Relay replication between
As a result, when the network line between the main site and the client site accessing the main site is interrupted, the storage of the subsite connected by another network line is relayed and the file access on the main site is continued. Can do.

  The embodiment of the present invention has been described above. However, in all the methods of the present invention described with reference to FIGS. 1 to 19, the same file system 312 is ported on each OS so that it does not depend on the OS platform. Thus, it is possible to configure so that the files in the storage of the main site 100 can be accessed.

  The main site 100, the client site 300, and the subsite 200 described above have a computer system therein. A series of processes related to the above-described process is stored in a computer-readable recording medium in the form of a program, and the above-described process is performed by the computer reading and executing this program.

  That is, in each process at the main site 100, the client site 300, and the subsite 200, a central processing unit such as a CPU reads the above program into a main storage device such as a ROM or RAM, and executes information processing and arithmetic processing. By doing so, it is realized.

  Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  The embodiment of the present invention has been described above. However, the replication volume dynamic generation system of the present invention is not limited to the above illustrated example, and various modifications can be made without departing from the gist of the present invention. Of course, can be added.

DESCRIPTION OF SYMBOLS 1 ... Dynamic generation system of replication volume, 100 ... Main site, 110 ... Host computer (host), 120 ... Storage, 131 ... File control area, 132 ... File data area, 140 ... Controller, 141 ... Area lock / transfer means, 142 ... Dynamic pair setting means, 143 ... Prefetch means, 144 ... Prefetch area index means, 145 ... MV RV pair management table, 146 ... reflection difference management table, 200 ... subsite, 210 ... host computer (host), 220 ... storage, 231 ... file control area, 232 ... file Data area, 240 ... Controller, 241 ... Area lock / transfer means, 242 ... Dynamic pair setting means, 245 ... MV / RV Management table, 246... Reflection difference management table, 247... Site switching management means, 300... Client site, 310... Host computer (host), 312. Area update means, 320 ... storage, 330 ... replication volume (RV), 331 ... file control area, 332 ... file data area, 340 ... controller, 341 ... area lock Transfer means, 342 ... Communication failure detection means, 343 ... Site switching means, 345 ... Dynamic pair setting means

Claims (5)

A main site having a plurality of master volumes (MV) in a storage unit and a client site having a replication volume (RV) in the storage unit for replicating the contents of the master volume are connected via a network, and the master volume A replication volume dynamic generation system in which a pair relationship is set between (MV) and the replication volume (RV),
Dynamic pair setting means for dynamically setting a pair relationship between the master volume (MV) and the replication volume (RV) of the client site when file access from the client site to the main site is performed,
A replication volume dynamic generation system characterized by comprising: The replication volume dynamic generation system includes:
And a subsite connected to the main site via the communication network and having a storage unit having a replication volume (RV) for replicating the contents of the master volume (MV) of the main site,
Dynamic pair setting means for dynamically setting the pair relationship between the master volume (MV) and the replication volume (RV) of the subsite when file access from the subsite to the main site is performed. The system for dynamically generating a replication volume according to claim 1, characterized in that: The main site is
An MV / RV pair management table describing the pair relationship;
A reflection difference management table that is associated with the pair relationship described in the MV / RV pair management table and stores the access frequency of the area accessed by file access to the master volume (MV);
Pre-reading area indexing means for determining an area where the access frequency of each master volume (MV) is high from the reflection difference management table;
Based on access frequency information read using the prefetch area indexing means, prefetching means for transmitting data with high access frequency in advance to the client site and subsite having the pair relationship;
With
The prefetch means transmits data to be transmitted in the master volume (MV) determined to have a high access frequency to the client site and subsite when the network line is available. about,
The dynamic generation system of a replication volume according to claim 1 or 2, characterized by the above-mentioned. The replication volume dynamic generation system includes:
A subsite connected to the main site via the communication network and having a storage unit having a replica volume (RV) for replicating the contents of the master volume (MV) of the main site;
The client site is
A communication failure detection means for detecting that the network line between the main site is disconnected,
A site switching unit that switches an access destination to the sub-site when the communication failure detection unit detects that the network line is disconnected;
With
The subsite is
Site switching management for obtaining information for relaying between the main site and the client site in response to a switching request from the site switching means of the client site;
Area lock / transfer means for relaying replication between the master volume (MV) at the main site and the replication volume (RV) at the client site;
The system for dynamically generating a replication volume according to any one of claims 1 to 3, further comprising: A main site having a plurality of master volumes (MV) in a storage unit and a client site having a replication volume (RV) in the storage unit for replicating the contents of the master volume are connected via a network, and the master volume A dynamic pair setting method in a dynamic generation system of a replication volume in which a pair relationship is set between (MV) and the replication volume (RV),
By the main site,
A dynamic pair setting procedure for dynamically setting the pair relationship between the master volume (MV) and the replication volume (RV) when file access from the client site to the main site is performed.
A dynamic pair setting method characterized by being performed.

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