Data processing system

This invention provides a control technique of a data processing system, in which functions of a highly-functional high-performance storage system are achieved in an inexpensive storage system so as to effectively use the existing system and reduce the cost of its entire system. This system has a RAID system, an external subsystem, a management server, a management client and the like. The management server includes an information management table for storing mapping information of the RAID system and the external subsystem. When performing copy process, the pair creation in which a logical volume of the RAID system is set as a primary volume of copy source and a logical volume of a mapping object of the RAID system mapped from the logical volume of the external subsystem is set as a secondary volume of copy destination is executed from the management client by using the information management table.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent Application JP 2004-249459 filed on Aug. 30, 2004, the content of which is hereby incorporated by reference into this application.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a technique for controlling a data processing system and more particularly to a technique effectively applied to the process for establishing a backup operating system using a data management function among plural storages.

BACKGROUND OF THE INVENTION

According to the examination by the inventor of the present invention, the following techniques are known as the control techniques for the conventional data processing systems.

For example, a database system for handling a large amount of data such as a data center adopts such a method that uses a storage system formed separately from its host system to manage data. This storage system is constituted of, for example, a disk array device and the like. The disk array device is constituted by arranging a large number of storage devices in the form of array and is established based on, for example, the redundant arrays of inexpensive disks (RAID). At least one logical volume is set on a physical storage area provided by the storage device group and this logical volume is provided to the host system. The host system is capable of writing or reading data to/from the logical volume by transmitting a predetermined command.

In such a database system, the amount of data managed by the database has been increasing day by day with the development of information society. For this reason, a higher-performance and larger-capacity storage system has been demanded and new storage systems have been developed to meet such a market demand. As a method for introducing a new storage system into a data processing system, for example, there are a method for replacing old storage system with a new storage system so as to constitute the data processing system all based on the new storage system (Published Japanese Translation of PCT Application No. 10-508967) and a method in which the new storage system is added to the data processing system of the old storage system so that the old and new storage systems coexist.

SUMMARY OF THE INVENTION

As a result of the examination by the inventor of the present invention for the control technique of the conventional data processing system described above, the following matters have been made evident.

As for the method for the transition from an old storage system to a new storage system as mentioned above (Published Japanese Translation of PCT Application No. 10-508967), although the function and performance of the new storage system can be utilized, the old storage system cannot be utilized effectively and introduction cost is high. On the other hand, as for the method for achieving coexistence of the old storage system and the new storage system, each storage system needs to prepare its own backup with its own management means, and further, the function of the new storage system is not utilized in the old storage system and the old storage system needs the functional improvement and the resultant cost is required.

Accordingly, an object of the present invention is to provide a technique for controlling a data processing system, in which advanced functions possessed by a new-type, highly-functional and high-performance storage system are achieved in a storage area of the old-type and inexpensive data storage system so as to make an effective use of the existing system and reduce the cost of its entire system.

The above and other objects and novel characteristics of the present invention will be apparent from the description and the accompanying drawings of this specification.

The typical ones of the inventions disclosed in this application will be briefly described as follows.

(1) The first data processing system according to the present invention comprises: a first storage system; a second storage system; a host system for executing data I/O with the first storage system; and a management unit for controlling the first storage system and the second storage system, in which the components are communicably connected among one another through a network, and the first data processing system has following characteristics in the establishment of the backup operating system using an online data copy function in the storage system.

That is, in the first data processing system according to the present invention, the first storage system has a first storage device and a first logical volume and a second logical volume which are set in the first storage device. The second storage system has a second storage device and a third logical volume which is set in the second storage device and mapped in the second logical volume of the first storage system. The management unit includes: an information management table which fetches configuration information of the first storage system and configuration information of the second storage system and stores mapping information of the second logical volume of the first storage system and the third logical volume of the second storage system; and pair creating means for executing the pair creation when performing copy process, in which the first logical volume of the first storage system is set as a primary volume of copy source and the second logical volume of the first storage system mapped from the third logical volume of the second storage system is set as a secondary volume of copy destination by using the information management table.

Further, the first storage system has a connecting function for connecting to the second storage system. The management unit has a management client, a management server, and a management agent each having management means for controlling a control device for issuing a command to the first storage system.

Also, when establishing a backup operating system, the management unit executes a discovery process for the first storage system by means of the management means, a setting process of a logical volume provided by the connecting function with using the management means, a pair creation process in which the first logical volume loaded on the first storage system is set as a primary volume and the second logical volume loaded on the first storage system mapped from the second storage system is set as a secondary volume by using the management means, and a confirmation process for the pair creation with using the GUI of the management client.

(2) The second data processing system according to the present invention comprises: a first storage system; a second storage system; a third storage system; a host system for executing data I/O with the first storage system and the third storage system; and a management unit for controlling the first storage system, the second storage system, and the third storage system, in which the components are communicably connected among one another through a network, and the second data processing system has following characteristics in the establishment of the backup operating system using a remote data copy function between storage systems.

That is, in the second data processing system according to the present invention, the first storage system has a first storage device and a second logical volume set in the first storage device. The second storage system has a second storage device and a third logical volume set in the second storage device and mapped in the second logical volume of the first storage system. The third storage system has a third storage device and a first logical volume set in the third storage device. The management unit includes: an information management table which fetches configuration information of the first storage system, configuration information of the second storage system, and configuration information of the third storage system and stores mapping information of the second logical volume of the first storage system and the third logical volume of the second storage system; and pair creating means for executing the pair creation when performing copy process, in which the first logical volume of the third storage system is set as a primary volume of copy source and the second logical volume of the first storage system mapped from the third logical volume of the second storage system is set as a secondary volume of copy destination by using the information management table.

Further, the first storage system has a connecting function for connecting to the second storage system. The management unit has a management client, a management server, and a management agent each having management means for controlling a control device for issuing a command to the first storage system.

Also, when establishing a backup operating system, the management unit executes a discovery process for the first storage system by means of the management means, a setting process of a logical volume provided by the connecting function with using the management means, a pair creation process in which the first logical volume loaded on the third storage system is set as a primary volume and the second logical volume loaded on the first storage system mapped from the second storage system is set as a secondary volume by using the management means, and a confirmation process for the pair creation with using the GUI of the management client.

The effect obtained by the representative one of the inventions disclosed in this application will be briefly described as follows.

According to the present invention, a high-speed and advanced function possessed by a highly-functional and high-performance storage system can be achieved in an inexpensive storage system, and consequently, the existing data processing system can be utilized effectively and the cost of the entire system can be reduced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that components having the same function are denoted by the same reference numerals throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

<Entire Structure of Data Processing System>

An example of the entire structure of the data processing system according to the embodiment of the present invention will be described with reference toFIG. 1.FIG. 1is a block diagram showing the entire structure of the data processing system.

As shown inFIG. 1, the data processing system of this embodiment comprises RAID systems100and150, an external subsystem400, an information processing unit500of a host system, and an information processing unit600of a management client. Hereinafter, the structure and function of the RAID system100will be mainly described, and the RAID system150also has the same structure and function.

The RAID system100is constituted as, for example, a disk array subsystem. The present invention is not limited to this example, and the RAID system100can be composed as a highly-functional intelligent-type fiber channel switch.

The RAID system100has a disk control unit200and a disk drive unit300. The disk control unit200controls the disk drive unit300in accordance with a command received from the information processing unit500of a host system. For example, the disk control unit200receives a data I/O request from the information processing unit500of the host system and reads/writes data stored in the storage device310provided in the disk drive unit300. Further, the disk control unit200receives various kinds of commands for controlling the RAID system100from the information processing unit600of a management client so as to carry out various settings of the RAID system100.

The external subsystem400has a storage device410. Additionally, it can include a channel control portion or a disk control portion. The external subsystem400is connected to the RAID system100through LAN (local area network) and SAN (storage area network), and the storage device410of the external subsystem400is handled as an internal storage device of the RAID system100.

The information processing units500and600of a host system and a management client are information devices such as a computer having CPU and memory. Various kinds of programs are executed by the CPU possessed by the information processing units500and600so as to achieve various functions. The information processing units500and600can be a personal computer or work station or a mainframe computer. Particularly, the information processing unit500of a host system is used as a central computer of bank's automatic teller machine or aircraft seat reservation system. Further, the information processing unit600of the management client is used as a control computer for maintenance and control of the RAID system100.

Referring toFIG. 1, the information processing unit500of a host system is communicably connected to a disk control unit200through SAN. The SAN is a network for exchanging data with the information processing unit500of the host system in units of block which is the data management unit in the storage sources provided by the disk drive unit300. Communication between the information processing unit500of the host system and the disk control unit200via the SAN is carried out according to a fiber channel protocol. Data access request in units of block is transmitted from the information processing unit500of the host system to the RAID system100according to the fiber channel protocol.

Further, the information processing unit500of the host system can be directly and communicably connected to the disk control unit200not through any network such as the SAN. Communication between the information processing unit500of the host system and the disk control unit200not through the network is made according to communication protocol such as fiber connection (FICON)(Registered Trademark), enterprise system connection (ESCON) (Registered Trademark), advanced connection architecture (ACONARC) (Registered Trademark), fiber connection architecture (FIBARC) (Registered Trademark) and the like. The data access request in units of block is transmitted from the information processing unit500of the host system to the RAID system100according to these communication protocols.

Of course, the information processing unit500of the host system and the disk control unit200may be connected not only by the SAN or directly without using the SAN but also through a local area network (LAN). If they are connected through the LAN, the communication therebetween can be made according to, for example, transmission control protocol/internet protocol (TCP/IP).

Also, the information processing unit600of the management client is connected to the disk control unit200through the LAN. The LAN can be of the Internet or of a dedicated network. The communication between the information processing unit600of a management client and the disk control unit200executed through the LAN is carried out according to, for example, the TCP/IP protocol. The data access request (data I/O request in units of file) by specifying a file name is transmitted to the RAID system100from the information processing unit600of the management client.

The disk drive unit300has a plurality of storage devices310. Consequently, it is possible to provide a large-capacity storage area to the information processing unit500of the host system and the information processing unit600of the management client. The storage device310can be formed of data storage medium such as hard disk or a plurality of hard disk drives which constitute redundant arrays of inexpensive disks (RAID). Further, it is possible to set a logical volume which acts as a logical storage area to the physical volume which is a physical storage area provided by the storage device310.

The disk control unit200and the disk drive unit300can be directly connected as shown inFIG. 1or can be connected through a network. Further, the disk drive unit300may be constituted integrally with the disk control unit200.

The disk control unit200comprises a channel control portion210, a shared memory220, a cache memory230, a disk control portion240, a control terminal250and a connecting portion260. The disk control unit200communicates with the information processing unit500of a host system through the SAN using the channel control portion210or directly without using the network.

The channel control portion210is provided with a communication interface for communicating with the information processing unit500of a host system and the information processing unit600of a management client and includes a function for exchanging data I/O commands with the information processing units500and600of the host system and the management client.

Each channel control portion210is connected to a control terminal250through an internal LAN. Consequently, a micro program to be executed by the channel control portion210is sent from the control terminal250and can be installed therein.

The connecting portion260connects the channel control portion210, the shared memory220, the cache memory230, the disk control portion240and the control terminal250among one another. Exchange of data and command among the channel control portion210, the shared memory220, the cache memory230, the disk control portion240and the control terminal250is carried out through the connecting portion260. The connecting portion260is constituted of, for example, a crossbar switch.

The shared memory220and the cache memory230are memories shared by the channel control portion210and the disk control portion240. While the shared memory220is mainly used for storing control information or command, the cache memory230is mainly used for storing data.

For example, when a data I/O request which a channel control portion210receives from the information processing unit500of the host system is a write command, the channel control portion210writes the write command into the shared memory220and writes the write data received from the information processing unit of the host system into the cache memory230. On the other hand, the disk control portion240monitors the shared memory220and when it detects that a write command is written into the shared memory220, it reads out the write data from the cache memory230in accordance with the command and writes it into the storage device310in the disk drive unit300.

Also, if the data I/O request which a channel control portion210receives from the information processing unit500of the host system is a read command, it is checked whether or not data to be read exists within the cache memory230. Here, if such data exists within the cache memory230, the channel control portion210sends the data to the information processing unit500of the host system. On the other hand, if no data to be read exists within the cache memory230, the channel control portion210writes a read command into the shared memory220and monitors the shared memory220. After detecting that the read command is written into the shared memory220, the disk control portion240reads the data to be read from the storage device310in the disk drive unit300and writes it into the cache memory230, and at the same time, writes a related note into the shared memory220. Then, when the channel control portion210detects that the data to be read is written into the cache memory230, the data is set to the information processing unit500of the host system.

In this way, data is exchanged between the channel control portion210and the disk control portion240through the cache memory230, and of the data to be stored in the storage device310, data read or written by the channel control portion210or the disk control portion240is stored in the cache memory230.

In addition to a structure in which data write or read from the channel control portion210to the disk control portion240is instructed indirectly through the shared memory220, for example, the structure in which the data write or read is instructed from the channel control portion210to the disk control portion240directly not through the shared memory220is also available. Further, a data I/O control portion may be provided by providing the channel control portion210with the function of the disk control portion240.

The disk control portion240is communicably connected to the plural storage devices310which storing data so as to control the disk drive unit300. For example, as described above, data read/write to the storage device310is executed in accordance with the data I/O request which the channel control portion210receives from the information processing unit500of the host system.

The respective disk control portions are communicably connected through the internal LAN together with the control terminal250. Consequently, a micro program to be executed by the disk control portion240can be transmitted from the control terminal250and installed therein.

Although the shared memory220and the cache memory230are provided independently of the channel control portion210and the disk control portion240in this embodiment, the present invention is not limited to this example, and it is also preferable that the shared memory220or the cache memory230may be provided separately in each of the channel control portion210and the disk control portion240. In this case, the connecting portion260mutually connects the channel control portion210and the disk control portion240having the dispersed shared memories220or the cache memories230.

The structure is also preferable in which at least any one of the channel control portion210, the disk control portion240, the connecting portion260, the shared memory220and the cache memory230is integrated with the other one.

The control terminal250is a computer for maintenance and control of the RAID system100. By operating the control terminal250, an operator can carry out setting of the configuration of the storage device310in the disk drive unit300, setting of a path which is a communication path between the information processing unit500of the host system and the information processing unit600of the management client and the channel control portion210, setting of logical volume and installation of a micro program to be executed in the channel control portion210and the disk control portion240. The settings of the configuration of the storage devices310in the disk drive unit300include the increase and decrease of the number of the storage devices310or the configuration change of the RAID (changing from the RAID1to RAID5).

Further, the control terminal250can perform the confirmation of the operating condition of the RAID system100, the determination of a fault position, and the installation of an operating system which the channel control portion210executes. These settings and controls can be carried out from a user interface included in the control terminal250or a user interface of the information processing unit600of the management client which displays a web page provided by the web server operating under the control terminal250. An operator can set an object and contents to be monitored about a trouble and a destination of notification about the trouble by operating the control terminal250.

The control terminal250can be incorporated in the disk control unit200or provided externally. Further, the control terminal250can be a computer dedicated for maintenance and control of the disk control unit200and the disk drive unit300or a general-purpose computer provided with maintenance and control function.

<Structure of Principal Part of Data Processing System>

An example of the structure of principal parts of the data processing system according to an embodiment of the present invention will be described with reference toFIGS. 2 and 21.FIG. 2is a block diagram showing the structure of the principal parts of the data processing system, andFIG. 21is a diagram showing the structure of principal parts of other example of the data processing system.

As for the data processing system of this embodiment, its entire structure and each function of the components are the same as those described in detail with reference toFIG. 1. The structure of the principal part which is a feature of this embodiment includes, as shown inFIG. 2, a RAID system100as a first storage system, an external subsystem400as a second storage system, an application server510as a host system (information processing unit500inFIG. 1) for executing data I/O with the RAID system100, and a management server610and management client620, which are management units (information processing unit600inFIG. 1) for controlling the configuration information of the RAID system100and the external subsystem400, and the RAID system100and the application server510are communicably connected to each other through the SAN. The RAID system100, the external subsystem400, the application server510, the management server610and the management client620are communicably connected among one another through the SAN.

This data processing system can establish a backup operating system by using a storage control software which is control means for controlling a control device for issuing a command to a storage subsystem, namely a software called command device manager (abbreviated as HDvM here).

The RAID system100is a storage subsystem having a function to connect external storages (external storage management: abbreviated as ESM) to be objects for the control by the HDvM. This ESM function is a technology for mapping a volume of an external storage subsystem within its own storage subsystem as a virtual volume. This RAID system100includes a storage device310, and a logical volume and a logical volume (virtual volume) which is an object for mapping are set in this storage device310. Further, the RAID system100includes an external port110which is connected to an external subsystem400through a data path. This external port is a port provided in the channel control portion210. Further, the control port is connected to LAN through a control path.

The external subsystem400is an object for control by the HDvM and is a storage subsystem to be an object for external storage of the RAID system100. This external subsystem400includes the storage device410and a logical volume to be mapped in a logical volume (virtual volume) which is a mapping object of the RAID system100is set in this storage device410. Further, the external subsystem400has a port420which is connected to the RAID system100through data path. Also, the control port is connected to the LAN through a control path.

As shown inFIG. 21, the external port110of the RAID system100and the port420of the external subsystem400can be connected by a data path through the SAN, and this structure also achieves the ESM function.

The management server610is a computer system for installing the HDvM server611. This management server610may be used as a management client. The management client620is a computer system in which the HDvM client621operates. This management client620may be incorporated in the management server610.

In the management server610and the management client620, the database of the management server610includes an information management table612for fetching the configuration information of the RAID system100and the configuration information of the external subsystem400and storing mapping information about logical volume (virtual volume) which is an object of mapping by the RAID system100and logical volume of the external subsystem400. In the copy process, the HDvM enables the pair creation from the GUI image622of the management client620, in which a logical volume of the RAID system100is set as a primary volume of copy source and a virtual volume mapped from a logical volume of the external subsystem400is set as a secondary volume of copy destination by using information management table612.

The application server510is a host computer system having the functions of the HDvM agent511and the RAID manager512.

This data processing system is a backup operating system including the RAID system100which provides the ESM function the and the HDvM of the storage control software and has an online copy function within the storage subsystem, namely a copy function called shadow image here. When this HDvM controls the configuration information necessary for backup operation by means of all the storage subsystems through the RAID system100, all the storage subsystems can be controlled integrally by the RAID system100and the HDvM.

<Process for Establishing Backup Operating System>

An example of the process for establishing the backup operating system in the data processing system according to an embodiment of the present invention will be described with reference toFIG. 3.FIG. 3is a flowchart showing the process of establishing the backup operating system.

In the following description, the logical volume is sometimes expressed as “volume”, “VOL” or “LDEV (logical device)”. If speaking in detail, this “LDEV” is a unit of a storage area divided logically. Further, the unit of a storage area which serves as a unit for I/O access is called “LU (logical unit)” and a single LU may be gained by combining plural LDEVs. The number for identifying this LU is “LUN (logical unit number)”. Further, of these logical volumes, the one set in the system is called internal volume and the one set outside is called external volume, while the one set virtually is called virtual volume. Additionally, a logical volume to be copied is called “PVOL (primary volume)” and a logical volume of copy destination is called “SVOL (secondary volume)”.

In the process of establishing the backup operating system, as shown inFIG. 3, first, discovery process of the RAID system100is carried out by the HDvM (S1). Further, the setting process of the LU provided by the ESM function using the HDvM is carried out (S2). Subsequently, pair creation process using the HDvM in which the internal LDEV loaded on the RAID system100is set as PVOL and the internal LDEV mapped from the external subsystem400is set as SVOL is carried out (S3). Then, confirmation process of the pair creation process by using a GUI image622of the management client621is carried out (S4). Consequently, the backup operating system is completed so that the mapped external volume can be used as SVOL of a shadow image.

<Discovery Process of RAID System (S1)>

An example of the discovery process (S1) of the RAID system will be described with reference toFIG. 4.FIG. 4is a flowchart showing the discovery process (S1) of the RAID system.

In the discovery process (S1) of the RAID system by the HDvM, as shown inFIG. 4, first, the HDvM client621requests the HDVM server612to detect the RAID system100(S1). Then, the HDvM server612detects the RAID system100by a RAID manager512, stores its information in the database within the management server610and notifies the HDvM client621of the registration of the RAID system100(S12–S14). Consequently, the detection of the RAID system100by the HDvM is completed.

<Setting Process of LU Provided by ESM Function (S2)>

An example of the setting process of the LU provided by the ESM function will be described with reference toFIGS. 5 to 7.FIG. 5is a flowchart showing the setting process (S2) of the LU provided by the ESM function,FIG. 6is an explanatory diagram showing an information management table necessary for mapping, andFIG. 7is an explanatory diagram showing the configuration for mapping by the ESM function.

In the setting process (S2) of the LU provided by the ESM function using the HDvM, as shown inFIG. 5, the RAID system100sets a port of the RAID system100in the external port110with using a storage navigator which is a subsystem control view of the RAID system100of the HDvM so that the RAID system100can use the ESM function (S21). Then, the external subsystem400is set with using the HDvM in order for the RAID system100to discover the external LU (S22).

In the setting of the external subsystem400, the port attribute of the external subsystem400to be connected to the external port110is changed (S22a). Then, this changed port is selected and “addition of storage” is executed (S22b). That is, a host system identified as the external port110is selected and the LUN security relating to accessibility from this host system is added.

Subsequently, the discovery of the external LU is executed with using the storage navigator so as to make the RAID system100recognize the external LU (S23). Then, the external LU is mapped on the internal LDEV with using the storage navigator in order to make the discovered external LU available in the RAID system100(S24).

In the mapping of this external LU to the internal LDEV, first, an external volume group is determined (S24a). That is, the external volume is registered in the management server610as an external volume group in order to map the external volume as the internal volume. Further, an IO suppression mode is determined (S24b). More specifically, input/output from a host system to a mapped volume is enabled when the external volume is mapped as an internal volume. Consequently, the mapped volume can be used from the host system as if it is a volume of the RAID system100. Then, an emulation type is set (S24c).

As shown inFIG. 6, the configuration information fetched from the RAID system100and the configuration information fetched from the external subsystem400are stored in the information management table612necessary for this mapping. The internal LUN information from the RAID system100includes virtual LUN information. The external LUN information of the external subsystem allocated to the virtual LUN of this RAID system100includes serial number of the external subsystem400(serial number), identification information of storage device (device ID), LUN number (external LUN) for identifying the LUN which is path information to the storage device, identification information (external WWN) unique to each port, and information of machine name (vender).

The LU to be set in the storage device410of the external subsystem400is mapped in this information management table612through the external port110as a virtual VOL set in the storage device310of the RAID system100. Consequently, a user can operate the internal LDEV mapped in the information management table612in the same way as that for the internal LDEV loaded on the RAID system100with using the HDvM as shown inFIG. 7.

<Pair Creation Process for PVOL and SVOL (S3)>

An example of the pair creation process for PVOL and SVOL will be described with reference toFIGS. 8 to 14.FIG. 8is a flowchart showing the pair creation process (S3) for PVOL and SVOL.FIG. 9is an explanatory diagram showing a selection screen of the storage subsystem for PVOL.FIG. 10is an explanatory diagram showing PVOL selection screen.FIG. 11is an explanatory diagram showing a copy type selection screen.FIG. 12is an explanatory diagram showing SVOL selection screen.FIG. 13is an explanatory diagram showing the detailed screen of SVOL.FIG. 14is an explanatory diagram showing pair creation process after PVOL and SVOL are determined.

In the pair creation process (S3) by using this HDvM, in which the internal LDEV loaded on the RAID system100is set as PVOL and the internal LDEV mapped from the external subsystem400is set as SVOL (S3), first, a storage subsystem to be set as PVOL is selected with using the GUI image622of the HDvM (S31).

In this selection, first, the RAID system100to be an object of the PVOL is selected (S31a). For example, in the GUI image622shown inFIG. 9, RAID-S@10.10.10.10 is selected from candidate storage subsystems. Then, PVOL is selected in an identification screen of the internal/external volumes (S31b). For example, in the GUI image622shown inFIG. 10, LDEV “0:35” is selected from an object list.

Further, a copy type of a selected PVOL is selected (S32) For example, in the GUI image622shown inFIG. 11, “shadow image” is selected from a selection of the copy types. After that, the external subsystem to be used as SVOL is selected (S33).

In this selection, external LUs which are not allocated yet and can be allocated depending on the size and emulation type are displayed (S33a). At this time, less expensive VOL (volumes) are sensed and displayed by priority. Further, SVOL (secondary volume) for pair creation is selected (S33b). For example, in the GUI image622shown inFIG. 12, LDEV “0:45” is selected from LDEV list. The “0:45” of this LDEV indicates the location of the storage subsystem (SATA-S@20.20.20.20). Then, the detailed information of the external subsystem400is confirmed (S33c). For example, in the GUI image622shown inFIG. 13, various identification numbers and identification information are displayed. This means that PVOL and SVOL are determined.

Subsequently, after PVOL and SVOL are determined, as shown inFIG. 14, the management server610instructs the application server510to create a pair (S34). Further, the HDvM agent511of the application server510issues a pair creation command to the RAID manager512(S35). Then, the RAID manager512throws a command line interface (CLI) command for pair creation to the RAID system100so as to execute the pair creation (S36).

<Confirmation Process of Pair Creation (S4)>

An example of the confirmation process (S4) of the pair creation will be described with reference toFIGS. 15 and 16.FIG. 15is an explanatory diagram showing the confirmation process (S4) for the pair creation, andFIG. 16is an explanatory diagram showing a pair creation completion screen.

In the confirmation process (S4) of the pair creation using the GUI image622of this management client620, as shown inFIG. 15, the management server610acquires information from the RAID system100or acquires information obtained by the RAID manager512through the HDvM agent511of the application server510so as to recognize it as copy pair information (S41). Thereafter, by delivering the information of the management server610to the management client620, the pair creation can be confirmed through the GUI image622of the management client620(S42). For example, the completion of the pair creation in which the LDEV “35” of RAID-S@10.10.10.10 which is the RAID system100is set as PVOL and the LDEV “45” of SATA-S@20.20.20.20 mapped from the external subsystem400is set as SVOL can be confirmed through the GUI image622as shown inFIG. 16.

The backup operating system as shown inFIG. 17is completed through the discovery process (S1) of the RAID system, the setting process (S2) of the LU provided by the ESM function, the pair creation process (S3) for PVOL and SVOL and the confirmation process (S4) of the pair creation. Consequently, a data processing system using the mapped external volume as a shadow image SVOL can be established. That is, a high-speed and advanced function possessed by the RAID system100can be applied to the LU of an inexpensive external subsystem400.

<Write Operation of Data into External Subsystem>

An example of the write operation of data into the external subsystem will be described with reference toFIG. 18.FIG. 18is an explanatory diagram showing the write operation of data into the external subsystem.

The host system such as the application server510can write data into the logical volume (LDEV) provided by the RAID system100. For example, it is possible to set the host system to access only a particular LDEV according to the zoning in which a virtual SAN subnet is set in the SAN or the LUN masking in which the host system holds a list of accessible LUNs.

If the LDEV to which the host system intends to write data is connected to the storage device310of the internal RAID system100through a virtual volume (VDEV: virtual device), the data is written through ordinary process. That is, the data from the host system is temporarily stored in the cache memory230and it is stored into a predetermined address of a predetermined storage device310from this cache memory230through the disk control portion240. At this time, the disk control portion240converts the logical address to the physical address. Further, in the case of the RAID configuration, the same data is stored in plural storage devices310.

Contrary to this, if LDEV to which the host system intends to write is connected to the storage device410of the external subsystem400through the virtual device, data is written in the manner shown inFIG. 18.FIG. 18(a) is a flowchart mainly showing memory hierarchy andFIG. 18(b) is a flowchart mainly showing the way of usage of the cache memory230.

First, the host system clarifies an LDEV number for specifying the LDEV of write destination and a WWN for specifying a port for accessing this LDEV and issues a write command (write) (S61). When the RAID system100receives a write command from the host system, it generates a write command to be sent to the external subsystem400and sends it to the external subsystem400(S62). The RAID system100changes write destination address information in the write command received from the host system in accordance with the external LDEV and generates a new write command.

Subsequently, the host system sends data to be written to the RAID system100(S63). Data received by the RAID system100is transmitted from the LDEV through the VDEV (S64) to the LDEV of the external subsystem400(S66). When the RAID system100stores data from the host system in the cache memory230, it sends back a response (good) indicating that the write is completed to the host system (S65). When the external subsystem400receives data from the RAID system100(or when write into the storage device410is completed), it sends a write completion notification to the RAID system100(S67). That is, the timing when the RAID system100notifies the host system of the write completion (S65) is different from the timing when data is actually stored in the storage device410(non-synchronous method). Therefore, the host system is released from the data write process before the data is actually stored in the storage device410and thus can execute other process.

<Operation for Reading Data from External Subsystem>

An example of the operation for reading data from the external subsystem will be described with reference toFIG. 19.FIG. 19is an explanatory diagram showing the operation for reading data from the external subsystem.

First, the host system specifies a port and sends a data read command to the RAID system100(S71). When the RAID system100receives the read command, it generates a read command to read a requested data from the external subsystem400. The RAID system100sends the generated read command to the external subsystem400(S72). The external subsystem400reads the data requested from the storage device410in accordance with the read command received from the RAID system100and sends it to the RAID system100(S73) and notifies that the read operation is completed normally (S75). As shown inFIG. 19(b), the RAID system100stores the data received from the external subsystem400at a predetermined location in the cache memory230(S74).

Subsequently, the RAID system100reads data stored in the cache memory230and converts its address. After that, it transmits the data to the host system through the LUN (S76) and notifies that the read operation is completed (S77).

FIG. 19shows the case where data is read from the external subsystem400in accordance with the request from the host system and stored in the cache memory230. However, the present invention is not limited to this example, and all or part of data stored in the external LDEV can be stored in the cache memory230in advance. In this case, it is possible to read data from the cache memory230immediately in response to a read command from the host system and send it to the host system.

<Structure of Principal Parts of Another Data Processing System>

An example of the structure of principal parts in another data processing system according to an embodiment of the present invention will be described with reference toFIG. 20.FIG. 20is a block diagram showing the structure of principal parts of another data processing system.

WhileFIG. 2shows the system configuration having the copy function called shadow image, the system configuration of another data processing system of this embodiment has a remote data copy function between the storage subsystems, that is, a copy function called true copy, and the RAID system150of copy source is added to the RAID system100of copy destination.

That is, this data processing system comprises, as shown inFIG. 20, the RAID system100which is a first storage system, the external subsystem400which is a second storage system, the RAID system150which is a third storage system, the application server510which is a host system for executing I/O of data between the RAID systems100and150, and the management server610and management client620which are management units for controlling the configuration information of the RAID systems100,150and the external subsystem400. The RAID system100, the RAID system150, and the application server510are communicably connected through the SAN, and the RAID system100, the RAID system150, the external subsystem400, the application server510, the management server610, and the management client620are communicably connected through the LAN.

According to this data processing system, a backup operating system using a mapped external volume as SVOL of true copy can be established by setting a PVOL of different storage subsystem in the above-described process of selecting a storage subsystem for PVOL (S31) in <Pair Creation Process for PVOL and SVOL (S3)>.

That is, by executing the pair creation process in which the internal LDEV loaded on the RAID system150is set as PVOL and the internal LDEV loaded on the RAID system100mapped from the external subsystem400is set as SVOL, a backup operating system can be established. Because other processes are the same as those in the case of the above-described shadow image, description thereof will be omitted.

As a result, a data processing system using the mapped external volume as SVOL of true copy can be established, and therefore, similar to the case of the shadow image, the high-speed and advanced function possessed by the RAID systems100and150can be applied to the LU of an inexpensive external subsystem400.

(1) When establishing a backup operating system which includes the RAID system100, the external subsystem400, the application server510, the management server610, and the management client620and uses the copy function called shadow image, a high-speed and advanced function possessed by the highly-functional and high-performance RAID system100can be achieved in a storage area of an inexpensive external subsystem400.

(2) When establishing a backup operating system which includes the RAID system100, the external subsystem400, the RAID system150, the application server510, the management server610, and the management client620and uses the copy function called true copy, a high-speed and advanced function possessed by the highly-functional and high-performance RAID systems100and150can be achieved in a storage area of an inexpensive external subsystem400.

(3) As a result of the above (1) and (2), existing system such as the external subsystem can be used effectively, and thus, the cost of the entire system can be reduced.