Storage system and storage subsystem

In the storage system, a storage apparatus includes a disk device for storing write data from a host computer as a primary volume and copied data of write data as a secondary volume, and a disk controller for collecting and managing status information of a plurality of copy pairs from the disk device with a primary volume and a secondary volume as a single copy pair. The disk controller monitors the status information of the plurality of copy pairs according to the status of failure, and, upon receiving a status notification command, transfers the detailed information concerning a copy pair as the status information of the copy pair subject to a failure, and flag information showing the overall status of all other copy pairs as status information of such other copy pairs.

CROSS REFERENCES

This application relates to and claims priority from Japanese Patent Application No. 2007-286652, filed on Nov. 2, 2007, the entire disclosure of which is incorporated herein by reference.

BACKGROUND

The present invention generally relates to a storage system configured from a host computer, a storage apparatus and a management computer, and to a storage subsystem storing information associated with access from the storage system and the host computer, and in particular to technology for acquiring the status of copy pairs configured with the storage apparatus.

The importance of nondisruptive operation and data protection in corporate information systems is ever-increasing due to the globalization of markets and the provision of 24/7 services via the Web. Nevertheless, there are numerous risks such as terrorism and natural disasters that may lead to the disruption or data loss of corporate information systems. In order to reduce these risks, it is necessary to assume that such disasters or failures will occur, and to plan in advance by when and how to restore the system that is shut down during the disaster or failure. This is known as “Disaster Recovery,” and will be hereinafter referred to as “DR.”

With DR, it is important to preliminarily set forth indexes indicating which data at what point in time is to be recovered by when, and operate the system while monitoring that such indexes are being observed. Among the foregoing indexes, the former; namely, the index showing which data at what point in time should be recovered is referred to as a “Recovery Point Objective” (hereinafter referred to as “RPO”), and the latter; namely, the index showing by when the business should be resumed after being affected by the disaster is referred to as a “Recovery Time Objective.”

Generally, a case where a volume to be copied is stored in the same storage apparatus as the foregoing volume is referred to as a local copy, and a case where a volume to be copied is stored in a different storage apparatus than the foregoing volume is referred to as a remote copy, and this is employed in information systems demanded of high reliability. Local copy and remote copy are sometimes collectively referred to as replication. According to this replication technology, even when a failure occurs in one of the volumes and becomes inoperable, the system operation can be continued by using the data stored in the other volume.

The two volumes of a copy source and a copy destination of a replication relationship are referred to as a copy pair. Normally, a copy pair is grouped in host computer units or application units, and the copy pair is controlled and monitored in such units. A plurality of copy pairs grouped in host computer units or application units are referred to as a copy group.

Remote copy is fundamental technology for realizing DR which prepares a remote site at a location that is geographically distant from the site (local site) conducting the business, and creates the entirely same data as the local site in the remote site.

There are two types of remote copy; namely, synchronous remote copy which returns a write completion reply to the server upon waiting for the data write completion reply on the remote site side when the business host issues an I/O [request], and asynchronous remote copy which returns a write completion reply to the server without waiting for the data write completion reply on the remote site side. With asynchronous remote copy, since it is possible to suppress the influence on the business reply performance even during the bandwidth fluctuation of the network or sudden fluctuations in the business load, this is effective when installing the remote site at a great distance or when using a network line with unstable performance.

Japanese Patent Laid-Open Publication No. 2007-47892 discloses technology concerning a storage system comprising a plurality of host computers and a plurality of storage apparatuses, wherein one storage apparatus controls the copy group extending across a plurality of storage apparatuses, and acquires the copy group and the copy pair status configuring such copy group.

SUMMARY

Incidentally, the size of storage systems is increasing exponentially pursuant to the advancement of the information society and the like. In connection with this, the scope of replication that must be monitored is also ever-increasing explosively. For instance, the number of copy pairs configuring a copy group to be used by a single application is on the verge of reaching several ten to hundred thousand copy pairs.

Meanwhile, asynchronous remote copy is characterized in that, when a failure occurs to even one copy pair configuring a copy group, all copy pairs configuring that copy group will be affected.

With asynchronous remote copy, it is necessary to maintain the consistency of the writing order in copy group units. Thus, if a pair link is disconnected as a result of a failure occurring in any one of the copy pairs configuring the copy group, the storage performs the operation of deleting the pair link of all copy pairs configuring the copy group. The RPO will increase if a failure occurs and the pair link is left in a disconnected state. Thus, in order to maintain the RPO, it is necessary to detect and correct a failure as soon as possible.

The present invention was made in view of the foregoing circumstances. Thus, an object of the present invention is to provide a storage system and a storage subsystem capable of inhibiting the increase of RPO by effectively monitoring the status of copy pairs configured by a storage apparatus and instantaneously detecting a failure that may cause the increase of RPO in a large-scale storage system.

In order to achieve the foregoing object, the present invention consolidates the status information of a plurality of [copy] pairs in a copy group obtained by grouping a plurality of copy pairs in a storage system, and changes the provision granularity of status information to the information request source computer according to the copy group status.

Specifically, proposed is a storage system in which a storage apparatus is provided with a primary storage unit for storing write data from the host computer as a primary volume, a secondary storage unit for storing copied data of write data stored in the primary storage unit as a secondary volume, and a status management unit for collecting and managing status information of a plurality of copy pairs from the primary storage unit and the secondary storage unit with a copy source primary volume and a copy destination secondary volume as a single copy pair. The status management unit monitors the status information of the plurality of copy pairs and transfers the status information of the copy pair subject to a failure to the management computer during a failure, and transfers only the flag information showing information of the overall copy pair to the management computer during a normal status.

As a result of adopting the foregoing configuration, it is possible to facilitate the cause unfolding by the administrator and thereby inhibit the increase of RPO during a failure.

DETAILED DESCRIPTION

First Embodiment

The first embodiment of the present invention is now explained. Incidentally, the present invention shall not be limited to the following embodiments explained below.

FIG. 1is a block diagram showing the configuration of a storage system according to the present embodiment. In this system, with the type of replication being a local copy to be performed in a single storage apparatus1500, the storage apparatus1500and a host computer1300are mutually connected via a data network1100. Although this embodiment explains a case where the data network1100is a storage area network, it may also be an IP (Internet Protocol) network or another data communication network.

The storage apparatus1500and a management computer1400are connected via a management network1200. Although this embodiment explains a case where the management network1200is an IP network, it may also be a storage area network or another data communication network. In addition, the data network1100and the management network1200may be the same network, and the management computer1400and the host computer1300may be the same computer.

For the sake of explanation, althoughFIG. 1shows a case where there is one storage apparatus1500, one host computer1300and one management computer1400, and the present invention is not limited to the foregoing configuration.

The storage apparatus1500is configured as a storage subsystem comprising a disk device1510for storing data, and a disk controller1520for controlling the storage apparatus [1520]. The disk device1510is configured from a plurality of volumes1511,1512,1513. The volumes1511,1512,1513may be physical volumes such as hard disk drives (HDDs), or logical volumes such as logical devices, and there is no particular limitation in the present invention. The volumes are able to configure a copy pair, and the operations to be performed to the copy pair and the status transition based on such operations will be described later.

Here, the disk device1510functions as a primary storage unit for storing write data from the host computer1300as a primary volume, and a secondary storage unit for storing the copied data of such write data stored in the primary storage unit as a secondary volume, and the disk controller1520functions as a status management unit for collecting and managing the status information of a plurality of copy pairs from the primary storage unit and the secondary storage unit with a copy source primary volume and a copy destination secondary volume as a single copy pair.

In the foregoing case, the disk controller1520monitors the status information of the plurality of copy pairs according to the status of failure, and, upon transferring information, transfers detailed information concerning a copy pair as status information of the copy pair subject to the failure to the management computer1400as an information request source, and transfers flag information showing the overall status of all other copy pairs as the status information of the other copy pairs to the management computer1400.

For the sake of explanation, althoughFIG. 1shows a case where there are three volumes, the present invention is not limited to the foregoing configuration.

The disk controller1520is provided with a host I/F1528, a management I/F1526, a disk I/F1525, a memory1521, a CPU1523, and a local disk1527. The local disk1527is a disk device such as a hard disk connected to the disk controller1520, and stores a storage microprogram1530. The storage microprogram1530is loaded in the memory1521of the disk controller1520, and executed by the CPU1523.

Although this embodiment explains a case where the storage microprogram1530is stored in the local disk1527of the disk controller1520, the present invention is not limited to the foregoing configuration. For example, these programs and tables may also be stored in a flash memory provided to the disk controller, or in an arbitrary disk in the disk device1510.

The storage microprogram1530receives a command from the management computer1400and/or host computer1300and controls the copy pair or acquires the copy pair status. As the control of copy pairs, there is the creation of a copy pair for newly creating copy pair, resynchronization of a copy pair for matching the contents of a secondary volume with the contents of a primary volume, and suspending of a copy pair for discontinuing the synchronous relationship. Acquisition of a copy pair status refers to the acquisition of information concerning which status the respective copy pairs are in based on the foregoing control. Transition of the copy pairs to the various statuses based on a control command will be described later. The management table1522stored in the memory1521will also be described later.

The host I/F1528is an interface to the data network1100, and sends and receives data and control commands to and from the host computer1300. The management I/F1526is an interface to the management network1200, and sends and receives data and control commands to and from the management computer1400. The disk I/F1525is an interface to the disk device1510, and sends and receives data and control commands.

The host computer1300is configured from an input device1340such as a keyboard or a mouse, a CPU1320, a display device1350such as a CRT, a memory1330, a storage I/F1360, and a local disk1310.

The storage I/F1360is an interface to the data network1100, and sends and receives data and control commands to and from the storage apparatus1500. The local disk1310is a disk device such as a hard disk connected to the host computer1300, and stores an application1312.

The application1312is loaded in the memory1330of the host computer1300, and executed by the CPU1320. The application1312is an application for reading and writing data from and into the volumes in the storage apparatus1500, and, for instance, is a DBMS or a file system.

For the sake of explanation, althoughFIG. 1shows a case where there is one application1312, the present invention is not limited to the foregoing configuration.

The management computer1400is configured from an input device1430such as a keyboard or a mouse, a CPU1440, a display device1450such as a CRT, a memory1420, a local disk1410, and a management I/F1460for sending and receiving data and control commands to and from the storage apparatus1500for system management.

The local disk1410is a disk device such as a hard disk connected to the management computer1400, and stores a management program1412. The management program1412is loaded in the memory1420of the management computer1400, and executed by the CPU1440.

The management program1412is a program for providing the function of operating and monitoring the copy pairs of one or more storage apparatuses via the input device1430such as a keyboard or a mouse or via the display device1450such as a graphical user interface (GUI). The management I/F1460is an interface to the management network1200, and sends and receives data and control commands to and from the storage1500. The management table1422in the memory1420will be described later.

FIG. 2shows the transition of the copy pair status. The statuses shown inFIG. 2, as indicated in the explanatory note2900, can be broadly classified into a stationary status2910, a transient status2920, and a failure status2930. Pair2100, Simplex2200, and Suspend2300are collectively referred to as a stationary status2910.

Copying2110and2120, Suspending2130, and Deleting2210are collectively referred to as a transient status2920. The difference between Copying2110and2120will be explained later. Error2800is referred to as a failure status2930.

The status transition from the stationary status2910to the transient status2920arises based on a command from the user. A command from a user is usually issued via the input device1340of the host computer1300, and received and executed by the storage microprogram1530loaded in the memory1521of the storage apparatus1500.

Nevertheless, the command from a user may also be issued via the input device1430of the management computer1400. The status transition from the transient status2920to the stationary status2910is conducted by the storage microprogram1530loaded in the memory1521of the storage apparatus1500without the intervention of the user's command.

Simplex2200is a status where a copy pair is not formed. When the copy pair status is Simplex2200, the copy pair status changes to Copying2110, which is one of the transient statuses2920, as a result of a copy pair creation command2115being issued by the user. Copying2110is a copy pair status showing that data is being copied from a primary volume to a secondary volume in order to make the corresponding copy pair into a synchronous status.

When the synchronization of the copy pair is complete, the copy pair status is changed from Copying2110to Pair2100without the intervention of the user's command. Pair2100is a copy pair status showing that the primary volume and the secondary volume are in synch.

As a result of a copy pair deletion command2218being issued from the user when the copy pair status is Pair2100, the copy pair status changes to Deleting2210, which is one of the transient statuses2920. Deleting2210is a copy pair status showing that the corresponding copy pair is deleting its copy pair relationship. When the deletion of the copy pair relationship is complete, the copy pair status changes from Deleting2210to Simplex2200without the intervention of the user's command.

As a result of a copy pair suspend command2135being issued from the user when the copy pair status is Pair2100, the copy pair status changes to Suspending2130, which is one of the transient statuses2920. Suspending2130is a copy pair status showing that the corresponding copy pair is suspending the copy pair relationship.

When the suspending of the copy pair relationship is complete, the copy pair status changes from Suspending2130to Suspend2300without the intervention of the user's command. Suspend2300is a copy pair status showing that, although the copy pair relationship is being maintained internally, the synchronization of the primary volume and the secondary volume is being discontinued.

As a result of a copy pair resynch command2125being issued from the user when the copy pair status is Suspend2300, the copy pair status changes to Copying2120, which is one of the transient statuses2920. Copying2110and Copying2120are the same in that data is copied from the primary volume to the secondary volume in order to make the copy pair a synchronous status. The difference is in that Copying2110copies all data of the primary volume to the secondary volume, while Copying2120only copies data that was written into the primary volume after the suspend command2135was issued to the secondary volume. When the synchronization of the copy pair is complete, the copy pair status changes from Copying2120to Pair2100without the intervention of the user's command.

As a result of a copy pair deletion command2215being issued from the user when the copy pair status is Suspend2300, the copy pair status changes to Deleting2210, which is one of the transient statuses2920. When the deletion of the copy pair relationship is complete, the copy pair status changes from Deleting2210to Simplex2200without the intervention of the user's command.

When some kind of failure occurs in Pair2100, Simplex2200, and Suspend2300as all stationary statuses2910and in Copying2110and2120, Suspending2130, and Deleting2210as all transient statuses2920, the copy pair status changes to Error2800.

FIG. 3shows the configuration of a copy group status determination table3000tabularizing the relationship of the status of the individual copy pairs configuring the copy groups, and the status of the copy groups. Although this embodiment explains a case where the copy group status determination table3000is retained in the storage microprogram1530, the present invention can also be implemented even if the copy group status determination table3000is stored separately from the storage microprogram1530; for instance, stored in the local disk1527of the storage apparatus or in a disk of the disk device1510.

As described above, a copy pair is usually grouped in host computer units or application units, and a copy pair is controlled or monitor in such units. A plurality of copy pairs grouped in host computer units or application units is referred to as a copy group.

The copy group status determination table3000is configured from a copy pair status field3100, a copy group status field3200, and a flag field3300.

The copy pair status field3100is a field displaying the status of the individual copy pairs configuring a copy group. For example, the field3105displays that the status of all copy pairs configuring a copy group is Simplex2200. The copy group status field3200is a field displaying the copy group status when the status of the respective copy pairs configuring the corresponding copy group is as shown in the copy pair status field3100.

The flag field3300is a field displaying whether the copy group is of a stationary status, a transient status or a failure status. Whether the copy group is a stationary status, a transient status or a failure status depends on the copy pair status.

FIG. 4,FIG. 5, andFIG. 6are configuration diagrams of a pair status table4000, a summary table5000, and an additional information table6000configuring the management table1522created in the memory1521of the storage apparatus1500. The respective tables are explained in detail below.

FIG. 4shows the configuration of the pair status table4000displaying information of the copy pairs configuring a copy group. The pair status table4000is configured from a copy group name field4100, a copy pair name field4200, a copy pair status field4300, a primary volume name field4400, and a secondary volume name field4500.

The copy group name field4100stores the name of the copy group. The copy pair name field4200stores the name of the copy pair. Although a copy pair is uniquely identified based on the primary volume name and the secondary volume name, since this alone will make management of a copy pair difficult, a copy pair is usually managed with a logical name as the copy pair name described above.

The copy pair status field4300stores the status of the copy pair. This field4300stores one status among Pair2100, Simplex2200, Suspend2300, Copying2110and2120, Suspending2130, Deleting2210, and Error2800shown inFIG. 2.

The primary volume name field4400stores the volume name of the primary volume of the copy pair. The secondary volume name field4500stores the volume name of the secondary volume of the copy pair.

According to the pair status table4000in this embodiment, the copy group CG.01 is configured from three copy pairs; namely, a copy pair4600named P1, a copy pair4700named P2, and a copy pair4800named P3, and the status of all of these copy pairs is Pair.

A copy group is normally defined by grouping a plurality of copy pairs in host computer1300units or application units at the start of operation. A copy group is defined by the copy group name, the copy pair name of the copy pairs configuring the copy group, a primary volume name, and a secondary volume.

When the copy group is defined, the storage apparatus1500creates a pair status table4000in the management table stored in the memory1521, and, based on the defined information, rewrites the copy group name field4100, the copy pair name field4200, the primary volume name field4400, and the secondary volume name field4500. Here, the pair status field4300is a blank column.

FIG. 5shows the configuration of a summary table5000displaying the copy group status as summary information. The summary table5000is configured from a copy group name field5100, a copy group status field5200, and a flag field5300.

The copy group name field5100displays the name of the copy group. The copy group status field5200displays the status of the copy group. The copy group status can be uniquely determined by referring to the copy group status determination table3000shown inFIG. 3if the status of the individual copy pairs configuring the copy group is known, and the value thereof is one among Simplex, Copying, Pair, Suspending, Suspend, Deleting, and Error.

The flag field5300is a field displaying whether the copy group is a stationary status, a transient status or a failure status. The value to be stored in the flag field5300can be uniquely determined by referring to the copy group status determination table3000shown inFIG. 3if the status of the individual copy pairs configuring the copy group is known, and the value thereof is one among a stationary status, a transient status, and a failure status.

FIG. 6shows the configuration of an additional information table6000storing additional information of the copy group. The additional information table6000is configured from a copy group name field6100and a concordance rate field6200.

The copy group name field6100displays the name of the copy group. The concordance rate field6200displays the concordance rate of the corresponding copy group. A concordance rate is an index showing the degree of synchronization between the primary volume and the secondary volume when the copy group status is Pair.

In this embodiment, the concordance rate of a copy group6300named CG.01 is shown to be 98%. The concordance rate is not referred to unless the status of the corresponding copy group is Pair.

The update processing of the management table1522created in the memory1521of the storage apparatus1500is now explained with reference to the flowchart7000ofFIG. 7. This update processing is performed by the storage microprogram1530loaded in the memory1521of the storage apparatus1500.

Foremost, the storage microprogram1530receives a management table update command (step7100). This command may be periodically performed by the microprogram1530by providing a timer to the storage microprogram1530, performed periodically provided by the management computer1400using the foregoing timer, or performed randomly according to instructions from the user.

Subsequently, the storage microprogram1530acquires all copy pair statuses configuring a copy group (step7200), and updates the pair status table4000based on the copy pair status acquired at step7200(step7300). Here, when the storage microprogram1530is to repeat the acquisition of the pair status without changing the configuration concerning a certain copy group, it updates only the copy pair status field4300in the pair status table4000.

The storage microprogram1530thereafter updates the copy group status field5200and the flag field5300of the summary table5000based on the copy group status determination table3000(step7400), refers to the copy group status field5200of the updated summary table5000, and checks whether the copy group status is Pair or of another status (step7500).

If the copy group status is Pair at step7500, the storage microprogram1530acquires the concordance rate of the copy group and stores it in the concordance rate field6200of the additional information table6000(step7600), stores the concordance rate of the copy group in the concordance rate field6200of the additional information table6000, and then ends the processing (step7700).

Meanwhile, if the copy group status is not Pair at step7500, the storage microprogram1530directly ends the processing (step7700).

FIG. 8shows the configuration of the transfer table determination table8000retained in the storage microprogram1530for determining the table to be transferred to the management computer1400. Although this embodiment explains a case where the transfer table determination table8000is retained in the storage microprogram1530, the present invention can also be implemented even if the transfer table determination table8000is stored separately from the storage microprogram1530; for instance, stored in the local disk1527of the storage apparatus or in a disk of the disk device1510.

The transfer table determination table8000is configured from a flag value field8100and a transfer table type field8200. The transfer table type field8200is configured from a summary table field8220, a pair status table field8240, and an additional information field8260.

The flag value field8100is one among stationary, failure or transient. The transfer table type field8200is configured from a summary table field8220, a pair status table field8240, and an additional information table field8260, and shows the table to be transferred according to the flag value.

The field indicating “√” shows the table to be transferred, and the field indicating “-” shows the table that does not need to be transferred. For example, if the flag value is the stationary status8320, the summary table5000and the additional information table6000are subject to transfer.

The operation upon receiving a copy pair status transfer command to be executed by the storage microprogram1530is now explained according to the flowchart9000ofFIG. 9.

Foremost, the storage microprogram1530receives a copy pair status transfer command (step9100). This command is usually issued by the management program1412of the management computer1400.

Subsequently, the storage microprogram1530refers to the flag value stored in the flag field5300of the summary table5000, further refers to the transfer table determination table8000, and determines the table among the three tables to be transferred according to the corresponding flag value (step9200).

The storage microprogram1530thereafter transfers the table determined to be transferred at step9200to the request source in the memory1521(step9300), and, when the transfer is complete, ends the processing (step9400).

FIG. 10andFIG. 11show the configuration of a copy group summary table10000and a copy group pair table11000configuring the management table1422created in the memory1420of the management computer1400. The respective tables are explained in detail below.

FIG. 10shows the configuration of the copy group summary table10000storing summary information of copy groups. The copy group summary table10000is configured from a copy group name field10100, a copy group status field10200, a flag field10300, and a concordance rate field10400.

The copy group name field10100displays the name of the copy group. The copy group status field10200displays the status of the copy group. The copy group status is one among Simplex, Copying, Pair, Suspending, Suspend, Deleting, and Error.

The flag field10300is a field displaying whether the copy group is of a stationary status, a transient status, or a failure status. The value stored in the flag field5300is one among stationary status, transient status, and failure status. The concordance rate field10400displays the concordance rate of the corresponding copy group. The concordance rate is referred to only when the status of the corresponding copy group is Pair.

FIG. 11shows a configuration of the copy group table11000storing the status of the individual copy pairs configuring a copy group. The configuration of the copy group table11000is the same as the pair status table4000displaying information of the copy pairs configuring the copy group shown inFIG. 4.

The copy group status acquisition processing to be executed by the management program1412loaded in the memory1420of the management computer1400is now explained with reference to the flowchart12000ofFIG. 12.

Foremost, the management program1412receives a copy group status acquisition command (step12100). This command may be performed by the management program1412as a result of providing a timer to the management program1412, or performed randomly according to the user's instructions.

Subsequently, the management program1412secures an area of maximum capacity obtainable from the storage apparatus as the management table1422in the memory1422of the management computer1400(step12200). This area is determined by the size of the copy group summary table10000, and the size of the copy group pair table11000in which the size of the area is determined based on the number of copy pairs configuring a copy group.

The management program1412thereafter issues a copy pair status transfer command to the storage apparatus1500(step12300). Here, the storage apparatus1500that received the copy pair status transfer command transfers the appropriate table to the management computer1400according to the flowchart shown inFIG. 9. In the foregoing case, one or more management tables are transferred from the storage apparatus1500to the management computer1400. These tables contain at least one summary table5000.

Thus, the management program1412rewrites the copy group status field10200and the flag field10300of the copy group summary table10000with the contents of the received summary table5000(step12400).

Subsequently, the management program1412checks whether the copy group status5200of the received summary table5000is Pair (step12500). If the copy group status5200of the received summary table5000is Pair at step12500, the management program1412rewrites the concordance rate field10400of the copy group summary table10000with the contents of the received additional information table6000(step12600).

Meanwhile, if the copy group status5200of the received summary table5000is not Pair at step12500, the management program1412checks whether the flag value of the received summary table5000is failure (step12700).

If the flag value is failure at step12700, the management program1412rewrites the pair status field4300of the copy group pair table11000with the contents of the received pair status table4000(step12800), and then ends the processing (step12900). If the flag value is a value other than failure at step12700, the management program1412directly ends the processing (step12900).

FIG. 13A,FIG. 13BandFIG. 13Cshows examples of the summary GUI13000to be displayed on the display device1450of the management computer1400. The summary GUI13000is configured from a copy group name field13100, a copy group status field13200, and a concordance rate field13300.

This GUI is created based on information of the copy group summary table10000created in the memory1420of the management computer1400. The copy group name field13100displays the name of the copy group. The copy group status13200displays the status of the copy group. The copy group status is one among Simplex, Copying, Pair, Suspending, Suspend, Deleting, and Error. The concordance rate field13300displays the concordance rate of the corresponding copy group. The concordance rate is indicated as N/A if the corresponding copy group status is other than Pair since a valid value is not entered.

FIG. 13Ashows the screen display example13400in a case when the copy group status is Pair. Since the copy group status is Pair, the pair concordance rate is displayed in the concordance rate field13300. The pair concordance rate is an index showing the level of synchronization between the primary volume and the secondary volume as described above.

If the pair concordance rate deteriorates, it is possible to predict that some kind of failure may occur. Thus, as a result of the pair concordance rate being displayed when the copy group status is Pair, even when it is the same Pair status, it is possible to know whether the status is free of any problem, or entails the possibility of leading to a failure.

FIG. 13Bshows the screen display example13500in a case when the copy group status is Error. Since the copy group status is Error, N/A is indicated in the concordance rate field13300. The copy group name displayed in the copy group name field13100can be clicked.

In order to pursue which copy pair is causing the failure among the copy pairs configuring the copy group, a screen displaying a list of copy pairs can be called from this screen. The called screen will be described later.

FIG. 13Cshows the screen display example13600in a case when the copy group status is Copying. Since the copy group status is Copying, N/A is displayed in the concordance rate field13300.

FIG. 14Ashows an example of the detailed GUI example14000to be displayed as a result of clicking the copy group name displayed on the copy group name field13100of the summary GUI13000when the copy group status is Error. The detailed GUI example14000is configured from a copy pair name field14100, a copy pair status field14200, a primary volume field14300, and a secondary volume field14400.

This GUI is created based on information of the copy group pair table11000created in the memory1420of the management computer1400. The copy pair name field14100displays the name of the copy pair. Although a copy pair is uniquely identified based on the primary storage apparatus and its volume number and the secondary storage apparatus and its volume number, since this alone will make management of a copy pair difficult, a copy pair is usually managed with a logical name as the copy pair name described above.

The copy pair status field14200displays the status of the copy pair. This field displays one status among Pair2100, Simplex2200, Suspend2300, Copying2110and2120, Suspending2130, Deleting2210, and Error2800shown inFIG. 2.

The primary volume14300displays the volume name of the primary volume of the copy pair. The secondary volume14400displays the volume name of the secondary volume of the copy pair.

According to the detailed GUI example14000in this embodiment, the copy group CG.01 is configured from three copy pairs; namely, a copy pair14500named P1, a copy pair14600named P2, and a copy pair14700named P3, and, since the copy pairs P1and P3are Pair, and [copy pair] P2is Error, it is evident that the copy pair P2is the cause of failure in the copy group CG.01.

FIG. 14Bshows an example of the detailed GUI example14001to be displayed as a result of the copy group name displayed on the copy group name field13100of the summary GUI13000when the copy group status is Error. The configuration of the table is the same as the table shown inFIG. 14A. The detailed GUI example14001only displays a pair in which the [copy] pair status is Error.

In a large-scale configuration, there are cases where a single copy group is configured from vast quantities of copy pairs of several ten thousand or more. Even in the foregoing case, the copy group status will be Error when just a couple of copy pairs are subject to a failure. When a failure occurs, as a result of displaying only the copy pair that is causing the failure, it is possible to promptly know the cause of failure even in the foregoing large-scale configuration.

As described above, data is not transferred from the primary volume to the secondary volume when a failure occurs. Thus, when a disaster occurs that will lead to the loss of data of the primary volume during the occurrence of a failure, data during this time will be lost. Since this implies the increase of RPO, it is important to promptly know the cause of failure and to provide a function for dealing with such failure.

This embodiment explained a case where, if the copy group status is Error, the detailed GUI example14000or the detailed GUI example14001is displayed as a result of clicking the copy group name displayed on the copy group name field13100of the summary GUI13000. Nevertheless, the detailed GUI example14000and the detailed GUI example14001may both be displayed by switching the screens with a tab or the like.

In this embodiment, when a copy pair status transfer command is issued from the management computer1400to the storage apparatus1500and the copy group status is a stationary status or a transient status, only the summary table5000and the additional information table5000in the management table1522managed in the storage apparatus1500in which the table size is independent of the number of copy pairs are transferred to the management computer1400, and the pair status table4000in which the size expands according to the number of copy pairs is not transferred.

Thus, according to this embodiment, when the copy group status is a stationary status or a transient status, the greater the number of copy pairs configuring a copy group, the reduction effect of the data transfer volume between the management computer1400and the storage apparatus1500will increase in comparison to conventional methods of transferring the status of all copy pairs configuring a copy group.

In addition, according to this embodiment, when the copy group status is a stationary status or a transient status, the copy group status can be known by displaying only the summary GUI13000on the display device1450of the management computer1400. The load of the screen display can be alleviated since it is not necessary to display the status of all copy pairs configuring a copy group.

Although this embodiment explained a case where there is one copy group in the storage apparatus1500, the present invention can be implemented by performing the following expansion even with a plurality of copy groups.

For example, the management table1522of the storage apparatus1500is expanded by creating one pair status table4000, one summary table5000, and one additional information table6000for each copy group. In the foregoing case, the update processing7000of the management table1522may be performed for each copy group, or collectively performed for all copy groups existing in the storage apparatus1500.

In addition, the management table1422of the management computer1400is expanded by creating one copy group summary table10000, and one copy group pair table11000for each copy group. In the foregoing case, the copy group status acquisition processing12000may be performed for each copy group, or performed collectively for all copy groups in the storage apparatus1500.

FIG. 15shows a display example of the summary screen15000displaying the results of the copy group status acquisition processing12000when a plurality of copy groups exist in the storage apparatus1500. Although the configuration of the summary screen15000is the same as the summary GUI13000, since a plurality of copy groups exist, the copy groups are displayed in a plurality of rows.

According to the summary GUI15000in this embodiment, there are a copy group15100named CG.01, a copy group15200named CG.02, and a copy group15300named CG.03, the status of the copy group CG.01 is Pair, the concordance rate is 98%, the status of the copy group CG.02 is Error, there is a link to the detailed GUI, and the status of the copy group CG.03 is Copying.

In this embodiment, during the processing900to be performed by the storage apparatus1500upon receiving the copy pair status transfer command, the storage apparatus1500refers to the flag value stored in the flag field5300of the summary table5000, further refers to the transfer table determination table8000, and, if the flag value is failure, transfers the summary table5000and the pair status table4000from the memory1521to the request source.

Nevertheless, the present invention can be implemented without transferring the pair status table4000from the memory1521to the request source when the flag value is failure. The difference in the case of not transferring the pair status table4000is explained below.

If the copy group status is not Pair at step12500of the copy group status acquisition processing12000to be executed by the management program1412in the management computer1400, the routine does not proceed to step12700, and the processing is ended directly.

There is no change to the summary GUI13000displayed on the display device1450of the management computer1400, and, when the copy group status is Error, the screen display example13500is displayed. The copy group name displayed on the copy group name field13100can be clicked, and, when this is clicked, the detailed GUI example14000is displayed.

The detailed GUI example14000is creates based on information of the copy group pair table11000created in the memory1420of the management computer1400, but the update processing of the copy group pair table11000is performed before referring to the information. A request of the pair status table4000is issued from the management computer1400to the storage apparatus1500, and the pair status table4000is transferred from the storage apparatus1500to the management computer1400. The management computer1400rewrites the pair status field4300of the copy group pair table11000with the contents of the received pair status table4000. After this processing is complete, the management program1412displays the detailed GUI example14000.

Here, even if the flag value is failure, since only the summary table5000is transferred to the request source during the initial request, the display response of the summary GUI13000in the management computer1400can be improved.

Second Embodiment

Although the type of replication was a local copy to be performed in a single storage apparatus1500in the first embodiment, the type of replication is a remote copy in the second embodiment, and the present invention can be implemented by expanding the first embodiment as follows. The difference with the first embodiment is explained below.

FIG. 16is a block diagram showing the configuration of a storage system in a case when the type of replication is a remote copy. InFIG. 16, the storage system comprises a storage apparatus1600for storing a secondary volume in addition to the storage apparatus1500for storing a primary volume.

The storage apparatus1500and the storage apparatus1600are mutually connected via a remote network1900. Although the remote network1900is a storage area network in this embodiment, it may also be an IP network or another data communication network. In addition, the configuration may be such that the network is partially a storage area network, and partially an IP network. The data network1100and the data network1800may also be the same network.

The storage apparatus1500and the storage apparatus1600comprise a remote I/F1650in the disk controller1520. The remote I/F1650is an interface to the remote network1900, and transfers data between the storage apparatus1500and the storage apparatus1600.

The host computer1700is mutually connected to the storage apparatus1600for storing the secondary volume via a data network1800. The configuration of the host computer1700is the same as the configuration of the host computer1300. Here, although the application1312is stored in the local disk1310as in the case of the storage apparatus1500storing the primary volume, the application1312may also be stored in a backup program.

Although the concordance rate was handled as additional information when the copy group status is Pair in the case of a local copy, primary/secondary differential time or buffer utilization (journal volume utilization) is handled as additional information in the case of a remote copy.

The primary/secondary differential time is a value showing the time difference between the timing that the data is written into the primary volume and the timing that the data is written into the secondary volume. In order to secure the reply performance in remote copy, there are cases where a write completion reply is returned to the host computer1300or1700at the time a data is written into the primary volume when a data write request is issued from the host computer1300or1700, and data is written into the secondary volume asynchronously with the writing of data into the primary volume.

This is referred to as an asynchronous remote copy. Since the time difference in the writing of data into the secondary volume depends on the network bandwidth of the remote network1900between the storage apparatus1500storing the primary volume and the storage apparatus1600storing the secondary volume, it is important to monitor the primary/secondary differential time.

In the asynchronous remote copy, when a write request is issued from the host computer1300or1700, the primary storage apparatus1500writes data into the volume of its own storage, and buffers the data until the writing of data into the volume of the secondary storage apparatus1600is complete. Buffer utilization is a value showing the usage level of the buffer. When the buffer continues to increase, or when the buffer exceeds a given value, it is possible to predict that some kind of failure will occur, and, therefore, it is important to monitor the buffer utilization.

FIG. 17shows the configuration of an additional information table17000storing additional information of the copy group. The difference between the additional information table17000and the additional information table6000is in that the primary/secondary differential time field17200and the buffer utilization field17300are provided in substitute for the concordance rate field6200as additional information.

FIG. 18shows the configuration of a copy group summary table18000storing summary information of the copy group. The difference between the copy group summary table18000and the copy group summary table10000shown inFIG. 10is in that a primary/secondary differential time field18400and a buffer utilization field18500are provided in substitute for the concordance rate field10400. According to the copy group summary table18000, it is evident that the copy group18100named CG.01 is Pair status, the primary/secondary differential time is 2 seconds, and the buffer utilization is 15%.

FIG. 19shows a display example of the summary GUI19000displayed on the display device1450of the management computer1400. The difference between the summary GUI19000and the summary GUI13000, a primary/secondary differential time field19300and a buffer utilization field19400are provided in substitute for the concordance rate field13300.

The difference between the processing method of the second embodiment and the processing method of the first embodiment is as follows. The processing sequence in the second embodiment regarding the update processing7000of the management table1522created in the storage apparatus1500is the same as the first embodiment. Nevertheless, although the concordance rate field6200of the additional information table6000was rewritten in the first embodiment during the additional information table update processing at step7600, the primary/secondary differential time field17200and the buffer utilization field17300of the additional information table17000are rewritten in the second embodiment.

The processing sequence in the second embodiment in the copy group status acquisition processing12000executed by the management program1412of the management computer1400is the same as the first embodiment, and the concordance rate field10400of the copy group summary table10000was rewritten with the contents of the received additional information table6000in the first embodiment during the additional information rewrite processing at step12600.

Meanwhile, in the second embodiment, the primary/secondary differential time field18400and the buffer utilization field18500of the copy group summary table18000are rewritten with the contents of the received additional information table17000. Other than the foregoing points, the second embodiment performs the same processing as the first embodiment.

In the second embodiment, with respect to the primary volume and the secondary volume of a plurality of copy pairs configuring a single copy group, the primary volume is stored in one storage apparatus1500and the secondary volume is stored in one storage apparatus1600. Nevertheless, the primary volume and the secondary volume of a plurality of copy pairs configuring a single copy group may also be respectively stored in a plurality of storage apparatuses.

In addition, although the second embodiment explains a case of connecting one storage apparatus1500to one host computer1300, it may also be connected to a plurality of host computers.

When a single copy group is configured across a plurality of storage apparatuses1500,1600as described above, the present invention can be implemented by defining one storage apparatus as a representative storage apparatus, and collecting the status of all copy pairs configuring the copy group in the storage of the representative storage apparatus.

The second embodiment is explained on the premise that a copy group configured from a plurality of copy pairs has been preliminarily defined in the management table1522of the storage apparatus1500, and the pair status table4000in the storage apparatus1500is created based on such defined information.

Nevertheless, even if the copy group information is not defined in advance, the present invention can be implemented by defining which copy pairs are configuring the copy group midway during the operation. An example of the implementing the present invention by defining the copy group information midway during the operation is explained below.

FIG. 20shows the configuration of a copy group definition command table20000to be issued from the management program1412of the management computer1400to the storage microprogram1530of the storage apparatus1500. The copy group definition command table20000is configured from a copy group name field20100, a copy pair name field20200, a primary volume name field20400, and a secondary volume name field20500.

The copy group name field20100displays the name of the copy group. The copy pair name field20200stores the name of the copy pair. Although a copy pair is uniquely identified based on the primary volume name and the secondary volume name, since this alone will make management of a copy pair difficult, a copy pair is usually managed with a logical name as the copy pair name described above. The primary volume name field20400stores the volume name of the primary volume of the copy pair. The secondary volume name field20500stores the volume name of the secondary volume of the copy pair.

According to the pair status table2000of this embodiment, the copy group CG.01 is configured from three copy pairs; namely, a copy pair20600named P1, a copy pair20700named P2, and a copy pair20800named P3.

The processing flow is explained below. The management program1412of the management computer1400issues a copy group definition command to the storage apparatus1500. This command includes the copy group definition command table20000.

When the storage microprogram1530of the storage apparatus1500receives a copy group definition command, it creates a pair status table4000in the management table stored in the memory1521, and rewrites the copy group name field4100, the copy pair name field4200, the primary volume name field4400, and the secondary volume name field4500with the contents of the copy group definition command table20000. The pair status field4300remains a blank column.

As a result of taking the foregoing step, the present invention can be implemented by performing the same processing as the processing described above after the foregoing processing. Although the copy group definition command was issued from the management program1412in the management computer1400in the foregoing example, this command may also be issued from the application1312in the host computer1300.

Third Embodiment

The third embodiment is configured such that an agent computer21100as an auxiliary management computer is disposed between the storage apparatus1500and the management computer1400, the agent computer21100and the storage apparatus1500are connected via a collection network21200, the agent computer [21100] and the management computer1400are connected via a management network1200, and the management computer1400sends and receives data to and from the storage microprogram1530in the storage apparatus1500via the agent computer21100, and the remaining configuration is the same as the first embodiment. The difference with the first embodiment is explained below.

FIG. 21shows the configuration of a storage system when the type of replication is a local copy. The present invention can also be implemented in a case where the type of replication is a remote copy. The configuration of the third embodiment is now explained below while focusing on the difference with the first embodiment.

The storage apparatus1500and the agent computer21100are connected via a data collection network21200. Although this embodiment explains a case where the data collection network21200is a storage area network, it may also be an IP network or another data communication network.

The agent computer21100and the management computer1400are connected via a management network1200. Although this embodiment explains a case where the management network1200is an IP network, it may also be a storage area network or another data communication network. In addition, the data network1100and the collection network21200may be the same network, and the agent computer21100and the host computer1300may be the same computer.

For the sake of explanation, although the third embodiment explains a case where there is one storage apparatus1500, one host computer1300, one management computer1400, and one agent computer, the present invention is not limited to the foregoing configuration.

The agent computer21100is configured from a CPU21140, a memory21120, a local disk21110, a data collection I/F21160for sending and receiving data and control commands to and from the storage apparatus1500for data collection, and a management I/F21170for sending and receiving data and control commands to and from the management computer1400for system management.

The local disk21110is a disk device such as a hard disk connected to the agent computer21100, and stores the management program21112. The management program21112is loaded in the memory21120of the agent computer21100, and executed by the CPU21140. The operation of the management program21112and the configuration of the management table21122will be described later.

The data collection I/F21160is an interface with the data collection network212200, and sends and receives data and control commands to and from the storage1500. The management table21122in the memory21120is configured from a pair status table4000, a summary table5000, and an additional information table6000. The configuration of the respective tables is the same as the first embodiment.

In the first embodiment, the copy group status determination table3000and the transfer table determination table8000were retained in the storage microprogram1530of the storage apparatus1500. In this embodiment, however, let it be assumed that these tables are retained in the management program21112of the agent computer21100. The present invention can also be implemented even when these tables are stored separately from the management program21112; for instance, stored in the local disk21110of the agent computer21100.

In the first embodiment, the management table1522created in the memory1521of the storage apparatus1500was configured from a pair status table4000, a summary table5000, and an additional information table6000. In this embodiment, however, the management table1522created in the memory1521of the storage apparatus1500is configured only from the pair status table4000.

In this embodiment, the copy groups are defined via the agent computer21100. In other words, when a copy group is defined, the storage microprogram1530of the storage apparatus1500creates a pair status table4000in the management table1522of the memory1521in the storage apparatus1500, and the management program21112of the agent [computer]21100creates a pair status table4000in the management table21122of the memory21120in the agent computer21100.

Here, the storage microprogram1530of the storage apparatus1500rewrites the copy group name field4100, the copy pair name field4200, the primary volume name field4400, and the secondary volume name field4500shown inFIG. 4based on the information defined upon creating the pair status table4000. Here, the pair status field4300is a blank column.

The operation upon receiving the copy pair status transfer command to be executed by the management program21112in the agent computer21100and the microprogram1530in the storage apparatus1500is now explained with reference to the flowchart ofFIG. 22. Although the copy pair status transfer command is issued from the management computer1400to the storage apparatus1500in the first embodiment, in this embodiment, it is issued from the management computer1400to the agent computer21100.

The processing of this embodiment is configured from the processing22100to be executed by the management program21112in the agent computer21100and the processing22500to be executed by the microprogram1530in the storage apparatus1500.

When the management program21112in the agent computer21100initially receives a copy pair status transfer command from the management computer1400(step22110), the management program21112in the agent computer21100issues a command for acquiring the status of all copy pairs to the microprogram1530in the storage apparatus1500(step22120).

When the microprogram1530in the storage apparatus1500receives the command for acquiring the status of all copy pairs from the management program21112in the agent computer21100, it acquires the status of all copy pairs (step22510), and rewrites the pair status field4300of the pair status table4000in the memory1521according to the acquired status of all copy pairs (step22510).

When the rewriting is complete, the microprogram1530in the storage apparatus1500transfers the updated pair status table4000to the agent computer21100(step22530).

When the management program21112in the agent computer21100receives the pair status table4000from the microprogram1530in the storage apparatus1500, it rewrites the [pair] status table4000in the memory of the agent computer21100according to the received information (step22130).

Subsequently, the management program21112in the agent computer21100updates the copy group status field5200and the flag field5300of the summary table5000based on the determination table3000(step22130), refers to the copy group status field5200of the updated summary table5000, and checks whether the copy group status is Pair or another status (step22150).

If the copy group status is Pair at step22150, the management program21112in the agent computer21100acquires the concordance rate of the copy group, stores the acquired concordance rate of the copy group in the concordance rate field6200of the additional information table6000(step22160), and then ends the processing (step22170).

If the copy group status is not Pair at step22150, the management program21112in the agent computer21100directly ends the processing (step22170).

Pursuant to the enlargement of replication, needs for collectively managing a plurality of storage apparatuses1500installed at a location that is geographically distant with a single management computer1400are increasing. This embodiment meets such needs.

In other words, when there are a plurality of storage apparatuses1500, an agent computer21100is installed for each storage apparatus1500, for each storage apparatus1500existing in a geographically similar location.

According to this embodiment, since the agent computer21100is disposed between the storage apparatus1500and the management computer1400, and the management computer1400sends and receives data to and from the storage microprogram1530in the storage apparatus1500via the agent computer21100, it is possible to reduce the load of communication between the agent computer21100and the management computer1400, and it is also possible to reduce the load of communication for collecting information from a plurality of storage apparatuses1500installed at a geographically distant location.

Further, according to this embodiment, since a significant portion of the processing that was performed by the microprogram1530in the storage apparatus1500in the first embodiment is performed by the agent computer21100, it is possible to reduce the management load of the storage apparatus1500.