Abstract:
To provide a storage connection changing method for a storage management system of setting and releasing an external connection between a primary storage system and an external storage system in a storage system, the storage management system includes a computer, the primary storage system, the external storage system, a network device, and a management device which manages the computer, the primary storage system, the external storage system, and the network device. The management device obtains a communication group information for limiting a communicable range between the computer and the storage systems from the network device, upon receiving of a request for changing an external connection state, And the management device generates a communication group information after the changing of the external connection state based on the request for changing the external connection state and the obtained communication group information.

Description:
CLAIM OF PRIORITY  
       [0001]     The present application claims priority from Japanese application P2004-220228 filed on Jul. 28, 2004, the content of which is hereby incorporated by reference into this application.  
       FIELD OF THE INVENTION  
       [0002]     This invention relates to a storage connection changing method which changes a storage external connection. More specifically, the invention relates to a technology which automatically sets an environment after a change of the external connection.  
       BACKGROUND OF THE INVENTION  
       [0003]     A connecting technology between computers and storage systems is changing from a connection by a Storage Area Network (SAN) using a Fibre Channel to a connection by a Storage Area Network via an IP-network (IP-SAN) such as an Internet Small Computer Systems Interface (iSCSI) or an Internet Fiber Channel Protocol (iFCP).  
         [0004]     The IP-SAN enables setting of an access limitation, a discovery domain and a Virtual LAN (VLAN).  
         [0005]     In the access limitation, a storage system which a connection initiator can access is set. Accordingly, the connection initiator can only access the storage system set in the access limitation.  
         [0006]     In the discovery domain, the same discovery domain is set in the same group (group composed of a connection initiator and a storage system connectable to the connection initiator). Accordingly, when a host computer or a administrator searches the connectable storage system, the storage system only in the same group is presented.  
         [0007]     The VLAN is set in a network device such as a router or a switch. Accordingly, a limitation is set to a range within which communication is capable through a second layer (data link layer) of an Open Source Initiative (OSI) reference model.  
         [0008]     High-level security measures can be implemented by setting a discovery domain in an Internet Storage Name Service (iSNS) server and the VLAN in the network device together with the access limitation in the storage system.  
         [0009]     Whereas, when a new storage system is introduced, an old storage system may be operating together with the new storage system. As a method of effectively using the old storage system in such a case, there is available a technology called an external connection function of a storage system. The external connection function is a technology which connects the new and old storage systems serially from the host computer, and shows a volume of the old storage system as that of the new storage system.  
         [0010]     When a connection state is changed (external connection is changed) in such an external connection function, the administrator must set the access limitation, the discovery domain, and the VLAN.  
         [0011]     Thus, there is known a technology which takes over the access limitation set in the old storage system by transferring data from the old storage system, to reduce a load on the administrator when the external connection is changed (refer to JP 2004-5370 A).  
       SUMMARY OF THE INVENTION  
       [0012]     According to the aforementioned conventional technology, the access limitation of the storage system can be automatically set when the external connection is changed. However, the discovery domain of the iSNS server or the VLAN of the network device cannot be automatically set.  
         [0013]     Consequently, the administrator must set a corresponding discovery domain or VLAN after the external connection is changed. This is a great load on the administrator. Besides, since such setting is complex, there is a possibility that the administrator will make a mistake in setting if a range of changing the external connection is wide.  
         [0014]     According to an embodiment of this invention, there is provided a storage connection changing method for a storage management system which changes an external connection state between a primary storage system and an external storage system in a storage system. The storage management system comprising a computer, the primary storage system directly accessed by the computer, the external storage system not directly accessed by the computer, a network device to connect the computer, the primary storage system and the external storage system, and a management device to manage the computer, the primary storage system, the external storage system and the network device. The method comprises: obtaining a communication group information for limiting a communicable range between the computer and the storage systems from the network device by the management device upon reception of a changing request of an external connection state; and generating a communication group information after the change of the external connection state by the management device based on the request for changing the external connection state and the obtained communication group information.  
         [0015]     According to the embodiment of this invention, in the case of changing the external connection, it is possible to automatically change the state of the storage management device after the external connection is changed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     The present invention can be appreciated by the description which follows in conjunction with the following figures, wherein:  
         [0017]      FIG. 1  is a block diagram of a storage management system according to an embodiment of this invention.  
         [0018]      FIG. 2  is a block diagram of a primary storage system according to the embodiment of this invention.  
         [0019]      FIG. 3  is a configuration diagram of logical volume constitution information stored in a database of a storage management sever according to the embodiment of this invention.  
         [0020]      FIG. 4  is a flowchart of a process of changing an external connection by a storage connection management server according to the embodiment of this invention.  
         [0021]      FIG. 5  is a configuration diagram of a changing the external connection request according to the embodiment of this invention.  
         [0022]      FIG. 6  is a configuration diagram of constitution information stored in the storage management server according to the embodiment of this invention.  
         [0023]      FIG. 7  is a configuration diagram of access limitation information stored in the storage management server according to the embodiment of this invention.  
         [0024]      FIG. 8  is a configuration diagram of node information stored in the storage management server according to the embodiment of this invention.  
         [0025]      FIG. 9  is a flowchart of a process of setting an access limit according to the embodiment of this invention.  
         [0026]      FIG. 10  is a configuration diagram of discovery domain information stored in an iSNS server according to the embodiment of this invention.  
         [0027]      FIG. 11  is a configuration diagram of iSNS node information stored in the iSNS server according to the embodiment of this invention.  
         [0028]      FIG. 12  is a flowchart of a process of setting a discovery domain according to the embodiment of this invention.  
         [0029]      FIG. 13  is a configuration diagram of VLAN group information stored in a network management server according to the embodiment of this invention.  
         [0030]      FIG. 14  is a configuration diagram of VLAN host information stored in the network management server according to the embodiment of this invention.  
         [0031]      FIG. 15  is a configuration diagram of interface information according to the embodiment of this invention.  
         [0032]      FIG. 16  is a flowchart of a process of setting a VLAN according to the embodiment of this invention.  
         [0033]      FIG. 17A  is a configuration diagram of volume information stored in an agent before the external connection is changed according to the embodiment of this invention.  
         [0034]      FIG. 17B  is a configuration diagram of volume information stored in the agent after the external connection is changed according to the embodiment of this invention.  
         [0035]      FIG. 18  is a configuration diagram of agent constitution information stored in the database according to the embodiment of this invention.  
         [0036]      FIG. 19  is a flowchart of a process of changing an external connection state according to the embodiment of this invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0037]     A preferred embodiment of this invention will be described below with reference to the accompanying drawings.  
         [0038]      FIG. 1  is a block diagram showing a configuration of a storage management system according to an embodiment of this invention.  
         [0039]     The storage management system of the embodiment of this invention is composed of a storage connection management server  100 , a network management server  111 , a storage management server  112 , an iSNS server  113 , a computer  114 , a primary storage system  116 , an external storage system  117 , and a switch  122 . For each of the computer  114 , the primary storage system  116 , the external storage system  117 , and the switch  122 , one device is shown, but two or more devices may be disposed.  
         [0040]     The storage connection management server  100  is coupled to the network management server  111 , the storage management server  112 , the iSNS server  113 , and the computer  114  through a management network  118 .  
         [0041]     Each of the iSNS server  113 , the computer  114 , the primary storage system  116 , and the external storage system  117  is coupled to the switch  122 . These components are coupled through the switch  122  to an IP network such as Internet. According to the embodiment of this invention, the management network  118  and the IP network are separate. However, they may be one and the same network.  
         [0042]     The storage connection management server  100  is composed of a CPU  101 , a memory  102 , a hard disk  103 , a bus  104 , and a network communication system  105 .  
         [0043]     The CPU  101  performs various operations by executing programs stored in the memory  102 . The memory  102  temporarily stores information or the like input/output on the hard disk  103 .  
         [0044]     The hard disk  103  stores a storage setting program  107 , an iSNS setting program  108 , a network setting program  109 , and an external connection changing program  110 . And the hard disk  103  stores a database  106 .  
         [0045]     The storage setting program  107  obtains and changes information of the storage management server  112  (e.g., information on setting of access limitation). The iSNS setting program  108  obtains and changes information of the iSNS sever  113  (e.g., information on setting of discovery domain). The network setting program  109  obtains and changes information of the network management server  111  (e.g., information on setting of VLAN). The external connection changing program  110  obtains and changes information of an agent  115  (e.g., information on setting of storage of connection target of computer  114 , described later). The database  106  stores the obtained information or the like.  
         [0046]     Each of the network management server  111 , the storage management server  112 , the iSNS server  113 , and the computer  114  is a computer equipment which is composed of a CPU, a memory, an I/O device, and a network interface. And the CPU of those computer equipments performs arithmetic operations by executing programs stored in the memory. According to the embodiment of this invention, the storage connection management server  110 , the network management server  111 , the storage management server  112 , and the iSNS server  113  are different computer equipments. However, these servers may be constituted on the same hardware.  
         [0047]     A disk drive is disposed in the primary storage system  116 , and three internal volumes  119  are constituted by the disk drive. Unique identifiers (LUN) of “1”, “2”, and “3” are set to the three internal volumes  119 .  
         [0048]     Similarly, the external storage system  117  is composed of two external volumes  121 . Unique identifiers (LUN) of “1” and “2” are set to the two external volumes  121 .  
         [0049]     The primary storage system  116  includes two virtual volumes  120  in addition to the internal volumes  119 . By setting the external volumes  121  of the external storage system  117  as the virtual volumes  120 , the primary storage system  116  seems as if it has the external volumes  121 .  
         [0050]     For example, when there is access to the virtual volume  120 , the primary storage system  116  relays it to the external volume  121  corresponding to the accessed virtual volume  120 .  
         [0051]     The computer  114  is composed of an agent  115  operated thereon. The agent  115 , when the external connection is changed, operates a logical volume to be accessed seems as if it is not changed from an application operated on the computer  114 .  
         [0052]      FIG. 2  is a block diagram showing a configuration of the primary storage system  116  according to the embodiment of this invention.  
         [0053]     The primary storage system  116  of the embodiment of this invention is composed of a controller  1160  and an interval volume  119 .  
         [0054]     The controller  1160  is composed of channel adaptors  1161 A,  1161 B, a CPU  1162 , a memory  1163 , a cache memory  1164 , and a disk adaptor  1165 .  
         [0055]     A control program is stored in the memory  1163 . The CPU  1162  performs various operations by loading and executing the control program.  
         [0056]     The controller  1160  controls data input/output on the internal volume  119  by operating the control program.  
         [0057]     The channel adaptor  1161 A is an interface for a primary system such as the computer  114  or the like. The channel adaptor  1161 A transfers data or a control signal with the iSNS server  113  and the computer  114  through the switch  122 .  
         [0058]     The channel adaptor  1161 B is an interface for the external storage system  117 . The channel adaptor  1161 B transfers data or a control signal with the external storage system  117  through the switch  122 .  
         [0059]     That is, the CPU  1162  controls the primary storage system  116  to seem as if it has an external volume  121  by transferring access to the virtual volume  120  of the primary storage system  116  from the channel adaptor  1161 A to the channel adaptor  1161 B.  
         [0060]     The disk adaptor  1165  is an interface for the internal volume  119 . For example, the disk adaptor  165  transfers data or a control signal with the internal volume  119  based on Fibre Channel protocol.  
         [0061]     The cache memory  1164  is a memory which temporarily stores data transferred between the channel adaptor  1161  and the disk adaptor  1165 .  
         [0062]      FIG. 3  is a configuration diagram showing logical volume constitution information stored in the database  106  of the storage connection management server  100  of the embodiment of this invention.  
         [0063]     The logical volume constitution information  150  includes an iSCSI name  151 , a Logical Unit Number (LUN)  152 , and external connection information  153 . The storage connection management server  100  manages the logical volume according to such information.  
         [0064]     The iSCSI name  151  is an identifier of an iSCSI node of the primary storage system  116 . The LUN  152  is an identifier of a logical volume set in the primary storage system  116 .  
         [0065]     The external connection information  153  includes an external connection flag  154 , a Remote iSCSI name  155 , and a Remote LUN  156 . The external connection flag  154  indicates whether the logical volume is a virtual volume  120 . That is, if the external connection flag  154  is “1”, its logical volume is a virtual volume  120 . If the external connection flag  154  is “0”, its logical volume is an internal volume  119 .  
         [0066]     The Remote iSCSI name  155  is an identifier of an iSCSI node of the external storage system  117  corresponding to the virtual volume. The Remote LUN  156  is an identifier of an external volume  121  corresponding to the virtual volume. The Remote iSCSI name  155  and the Remote LUN  156  are used only when the external connection flag  154  is “1” (a logical volume is the virtual volume  120 ), and not used when the flag is “0” (a logical volume is the internal volume  119 ).  
         [0067]     According to the embodiment of this invention, the iSCSI name  151  of the primary storage system  116  is a “storage 1”, and the iSCSI name  151  of the external storage system  117  is a “storage 2”.  
         [0068]     The “storage 1” has internal volumes  119  of LUNs “1”, “2”, and “3”, and a virtual volume  120  of LUN “4”. When there is access to the virtual volume  120  of the LUN “4”, the primary storage system  116  (storage 1) transfers the access to the external volume of the LUN “1” of the external storage system  117  (storage 2).  
         [0069]     The storage connection management server  100  notifies the logical volume constitution information  150  according to a request of an administrator  123 . The administrator  123  refers to the logical volume constitution information  150 , and requests the storage connection management server  100  to change the external connection when a change of the external connection is necessary.  
         [0070]     Upon reception of the external connection changing request of the primary storage system  116  from the administrator  123 , the storage connection management server  100  automatically sets an access limitation, a discovery domain, a VLAN, and an external connection state. At this time, the storage connection management server  100  automatically sets such based on information obtained from the storage management server  112 , the iSNS server  113 , the network management server  111 , the agent  115  and the like.  
         [0071]     Hereinafter, description will be made of a change of the external connection when the primary storage system  116  (storage 1) controls the LUN “2” of the external storage system  117  (storage 2) to seem as if it is a LUN “5” of the primary storage system  116  (storage 1).  
         [0072]      FIG. 4  is a flowchart showing a process of changing the external connection by the storage connection management server  100  according to the embodiment of this invention.  
         [0073]     First, the storage connection management server  100  receives a changing request of the external connection shown in  FIG. 5  from the administrator  123  ( 201 ).  
         [0074]      FIG. 5  is a am configuration diagram showing the request of changing the external connection according to the embodiment of this invention. This changing request of the external connection is for controlling the LUN “2” of the “STORAGE 2” to seem as if it is a LUN “5” of the “STORAGE 1”.  
         [0075]     The changing request of the external connection  220  includes a setting type  221 , a storage system name  226 , an iSCSI name  222 , a LUN  223 , a Remote iSCSI name  224 , and a Remote LUN  225 .  
         [0076]     The setting type  221  is “SET” or “RELEASE”. The “SET” means a request to set a new external connection. The “RELEASE” means a request to release the set external connection.  
         [0077]     Referring back to  FIG. 4 , after the storage connection management server  100  has received the changing request of the external connection  220 , the storage setting program  107  sets an access limitation for the storage management server  112  as shown in  FIG. 9  ( 202 ).  
         [0078]     Next, the iSNS setting program  108  sets a discovery domain for the iSNS server  113  as shown in  FIG. 12  ( 203 ).  
         [0079]     Then, the network setting program  109  sets a VLAN for the network management server  111  as shown in  FIG. 16  ( 204 ).  
         [0080]     Further, the external connection changing program  110  changes an external connection state as shown in  FIG. 18  ( 205 ).  
         [0081]     Thus, the changing of the external connection is completed.  
         [0082]     Next, the process of setting the access limitation (step  202  of  FIG. 4 ) will be described in detail.  
         [0083]     First, various information used for the process of setting the access limitation will be described.  
         [0084]     The storage management server  112  stores constitution information, an access limitation information, and a node information (these are shown in  FIG. 6  to  FIG. 8 ). The storage management server  112  notifies such information according to a request from the storage connection management server  100  the primary storage system  116  or the external storage system  117 .  
         [0085]     The storage management server  112 , the storage connection management server  100 , the primary storage system  116 , and the external storage system  117  communicate with one another by using a Simple Network Management Protocol (SNMP) or a Common Information Model (CIM). Additionally. An API or a protocol of storage management server  112 &#39;s own may be used.  
         [0086]      FIG. 6  is a configuration diagram showing the constitution information stored in the storage management server  112  of the embodiment of this invention.  
         [0087]     One record of the constitution information  310  is prepared for each storage system, and includes a storage system name  311  and storage constitution information  312 .  
         [0088]     The storage system name  311  is an identifier of a storage system. The constitution information  310  of this embodiment contains a record in which the storage system name  311  is a “STORAGE 1” and a record in which the storage system name  311  is a “STORAGE 2”.  
         [0089]     The storage constitution information  312  includes an iSCSI name  313 , a LUN  314 , and an external connection iSCSI name  315 .  
         [0090]     The iSCSI name  313  is an identifier of an iSCSI node of the storage system. The LUN  314  is an identifier of a logical volume set in the storage system. The external connection iSCSI name  315  is an identifier of an iSCSI node of a port through which the storage system accesses the external storage system.  
         [0091]     Each of the iSCSI name  313 , the LUN  314 , and the external connection iSCSI name  315  can have a plurality of values when plural identifiers sets are in one storage system.  
         [0092]      FIG. 7  is a configuration diagram showing the access limitation information stored in the storage management server  112  of the embodiment of this invention.  
         [0093]     The access limitation information  320  includes an Initiator iSCSI name  321 , a Target iSCSI name  322 , and a LUN  323 . The Initiator iSCSI name  321  is an identifier of an iSCSI node of a connection initiator. The Target iSCSI name  322  is an identifier of an iSCSI node of a storage system of a connection target. The LUN  323  is an identifier of a logical volume set in the storage system of the connection target.  
         [0094]     Upon receiving of a request of reading/writing in the logical volume from the computer  114  or the like, the storage system obtains the access limitation information  320  from the storage management server  112 . Then, by referring to the obtained access limitation information  320 , the storage system compares the requested identifier of the computer  114  or the like with the Initiator iSCSI name  321 , and further compares its own identifier with the Target iSCSI name  322 . Only when both of Initiator iSCSI name and Target iSCSI name coincide with each other, the storage system permits reading/writing in the logical volume.  
         [0095]     In the access limitation information  320  of the embodiment, the connection initiator and the connection target to which access is permitted are stored. However, a connection initiator and a connection target to which access is not permitted may be stored.  
         [0096]      FIG. 8  is a configuration diagram showing node information stored in the storage management server  112  of the embodiment of this invention.  
         [0097]     The node information  330  includes a storage system name  331 , a port name  332 , an attribute  333 , and an iSCSI name  334 .  
         [0098]     The storage system name  331  is an identifier of a storage system. The port name  332  is an identifier of a port of the storage system.  
         [0099]     The attribute  333  is an attribute of the port, which is “Target” or “External”. If the storage system is a connection target, the port that has a Target attribute is used. On the other hand, if the storage system is a connection initiator, the port that has an External attribute is used. The iSCSI name  334  is an identifier of an iSCSI node of the port.  
         [0100]      FIG. 9  is a flowchart showing a process of setting an access limitation in step  202  of  FIG. 4 .  
         [0101]     First, the storage setting program  107  extracts the setting type  221  from the changing request of the external connection  220 , and determines whether to set or release the external connection ( 301 ).  
         [0102]     When setting the external connection, the storage setting program  107  extracts the storage system name  226  (storage 1) from the changing request of the external connection  220 . Next, the storage setting program  107  obtains the node information  330  from the storage management server  112 .  
         [0103]     Then, the storage setting program  107  extracts the iSCSI name  334  which coincides with the storage system name  331  and the storage system name  226  (storage 1) extracted from the changing request of the external connection  220 , and whose attribute is “External” from the obtained node information  330 . In the case of the node information  330  shown in  FIG. 8 , “EXTERNAL CONNECTION 1” is extracted.  
         [0104]     The storage setting program  107  stores the obtained iSCSI name  334  (external connection 1) as a registration standby node in the database  106  ( 302 ).  
         [0105]     The storage setting program  107  obtains a record of the access limitation information  320  in which the iSCSI name (external connection 1) of the registration standby node coincides with the Initiator iSCSI name  321  from the storage management server  112  ( 304 ).  
         [0106]     Then, the storage setting program  107  collates the changing request of the external connection  220  with the obtained record of the access limitation information  320 . In detail, the storage setting program  107  compares the Remote iSCSI name  224  (storage 2) with the Target iSCSI name  322 , and the Remote LUN  225  (2) with the LUN  323 . The storage setting program  107  determines whether there is a record of which both of the iSCSI name and the LUN coincide in access limitation information  320   
         [0107]     The storage setting program  107  finishes the processing if there is a record of which both of the iSCSI name and the LUN coincide in access limitation information  320 . On the other hand, if there is no record of which both of the iSCSI name and the LUN coincide in access limitation information  320 , the storage setting program  107  sends a request of setting the access limitation information  320  which contains information on the iSCSI name (external connection 1) of the registration standby node and the changing request of the external connection  220  to the storage management server  112 .  
         [0108]     Upon receiving of the request of setting the access limitation information  320 , the storage management server  112  sets the storage system name  226  (storage 1) of the changing request of the external connection  220  in the storage system name  311  of the constitution information  310 . Additionally, the storage management server  112  sets the iSCSI name  222  (storage 1) of the changing request of the external connection  220  in the iSCSI name  313 , a LUN  223  (5) of the changing request of the external connection  220  in the LUN  314 , and the iSCSI name (external connection 1) of the registration standby node in the external connection iSCSI name  315 .  
         [0109]     In this case, when the same name is present in the storage system name  311 , values only of the LUN  314  and the external connection iSCSI name  315  are added. That is, according to the embodiment of this invention, “5” needs be added to the LUN  314  of the constitution information  310 .  
         [0110]     Next, the storage management server  112  sets the iSCSI name (external connection 1) of the registration standby node in the Initiator iSCSI name  321  of the access limitation information  320 . Additionally, the storage management server  112  sets the Remote iSCSI name  224  (storage 2) of the changing request of the external connection  220  in the Target iSCSI name  322 , and the Remote LUN  225  (2) of the changing request of the external connection  220  in the LUN  323  ( 305 ).  
         [0111]     At this time, when there are identical names in the Initiator iSCSI name  321  and the Target iSCSI name  322 , a value only of the LUN  323  is added. That is, according to the embodiment of this invention, “2” needs be added to the LUN  323 .  
         [0112]     On the other hand, when the external connection is released in step  301 , the process proceeds to step  303 . By referring to the access limitation information  320 , the storage setting program  107  compares the iSCSI name  222  of the changing request of the external connection  220  with the Target iSCSI name  322 , and further compares the LUN  223  of the changing request of the external connection  220  with the LUN  323 . Then, the storage setting program  107  obtains the Initiator iSCSI name  321  of the record in which both of the iSCSI name and the LUN coincide from the storage management server  112 .  
         [0113]     Then, the storage setting program  107  stores the obtained Initiator iSCSI name  321  as an iSCSI name of a registration standby node in the database  106  ( 303 ).  
         [0114]     The subsequent process is similar to that of step  304  and after when the external connection is set.  
         [0115]     Next, the process of setting the discovery domain (step  203  of  FIG. 4 ) will be described in detail.  
         [0116]     First, various information used for the process of setting the discovery domain will be described.  
         [0117]     The iSNS server  113  stores discovery domain information and an iSNS node information (these are shown in  FIG. 10  and  FIG. 11 ). The iSNS server  113  notifies information according to a request from the storage connection management server  100  or the switch  122 . Here, the iSNS server  113 , the storage connection management server  100 , and the switch  122  communicate with one another by using the SNMP.  
         [0118]      FIG. 10  is a configuration diagram showing the discovery domain information stored in the iSNS server  113  of the embodiment of this invention.  
         [0119]     The discovery domain information  410  includes a discovery domain name  411 . The discovery domain name  411  uniquely identifies a group. By setting the same discovery domain name in the same group (group composed of a connection initiator and a storage connectable to the connection initiator), the storage system in the same group can be presented when the administrator  123  or the computer  114  searches the connectable storage system.  
         [0120]     Referring to  FIG. 10 , “DD1” and “DD2” are set in the discovery domain name  411 . The discovery domain information  410  of  FIG. 10  shows after the completion of changing the external connection to control the LUN “2” of the “STORAGE 2” to seem as if it is the LUN “5” of the “STORAGE 1”. Initially, the “DD1” only is set in the discovery domain information  410 .  
         [0121]      FIG. 11  is a configuration diagram showing the iSNS node information stored in the iSNS server  113  of the embodiment of this invention.  
         [0122]     The iSNS node information  420  includes an iSCSI name  421  and a discovery domain name  422 . According to the embodiment of this invention, the iSCSI name  421  is set in the iSCSI node of the “COMPUTER 1” and the “STORAGE 1”, and the discovery domain name  422  is set in the “DD1”. The “COMPUTER 1” is an iSCSI name of the computer  114  connected to the primary storage system  116  (storage 1). For example, when the “COMPUTER 1” searches the connectable storage system, the “STORAGE 1” in which the same discovery domain name  421  (DD 1) is set is presented.  
         [0123]     In the iSNS node information  420  of  FIG. 11 , the iSCSI name  421  is set in a record of the iSCSI node of the “EXTERNAL CONNECTION 1” and the “STORAGE 2”, and the discovery domain name  422  is set in the “DD2”. The iSNS node information  420  of  FIG. 11  show after the completion of changing the external connection to control the LUN “2” of the “STORAGE 2” to seem as if it is the LUN “5” of the “STORAGE 1”. Initially, these records are not set in the iSNS node information  420 .  
         [0124]      FIG. 12  is a flowchart showing the process of setting the discovery domain in step  203  of  FIG. 4 .  
         [0125]     First, the iSNS setting program  108  obtains the discovery domain information  410  and the iSNS mode information  420  from the iSNS server  113  ( 401 ).  
         [0126]     Next, the iSNS setting program  108  extracts the setting type  221  from the changing request of the external connection  220 , and determines whether to set or release the external connection ( 402 ).  
         [0127]     When setting the external connection, the iSNS setting program  108  creates a “DD2” of a new discovery domain name not contained in the obtained discovery domain information  410 . Then, the iSNS setting program  108  adds and sets the created discovery domain name (DD2) in the discovery domain information  410  ( 403 ).  
         [0128]     Next, the iSNS setting program  108  obtains the storage system name  226  (storage 1) from the changing request of the external connection. By referring to the constitution information  310 , the iSNS setting program  108  extracts an external connection iSCSI name  315  (external connection) in which the obtained storage system name  226  (storage 1) coincides with the storage system name  311 . The iSNS setting program  108  sends an iSNS node addition request. The iSNS node addition request includes the obtained external connection iSCSI name  315  (external connection 1) and the created discovery domain name (DD2) to the iSNS server  113 .  
         [0129]     Similarly, the iSNS setting program  108  sends an iSNS node addition request. The iSNS node addition request includes the Remote iSCSI name  224  (storage 2) of the changing request of the external connection  220  and the created discovery domain name (DD2) to the iSNS server  113 .  
         [0130]     Upon reception of the iSNS node addition request, the iSNS server  113  adds the Remote iSCSI name  224  (storage 2) to the iSCSI name  421  of the iSNS node information  420 . Further, the iSNS server  113  adds the discovery domain name (DD2) of the iSNS node addition request to the discovery domain name  422  of the added record of the iSNS node information  420 . Then, the iSNS node information  420  is set as shown in  FIG. 10 .  
         [0131]     By this process, the external connection iSCSI node of the primary storage system  116  and the iSCSI node of the external storage system  117  are set to belong to the new discovery domain ( 404 ).  
         [0132]     On the other hand, when the external connection is released in step  402 , the process proceeds to step  405 . The iSNS setting program  108  extracts from the iSNS node information  420 , the discovery domain name  422  in which the iSCSI name  222  of the changing request of the external connection  220  coincides with the iSCSI name  421  of the iSNS node information  420 .  
         [0133]     Next, the iSNS setting program  108  sends the iSNS node addition request. The iSNS node addition request includes the Remote iSCSI name  224  of the changing request of the external connection  220  and the extracted discovery domain name  422  to the iSNS server  113 .  
         [0134]     Upon reception of the iSNS node addition request, the iSNS server  113  adds the Remote iSCSI name  224  to the iSCSI name  421  of the iSNS node information  420 . Further, the iSNS server  113  adds the discovery domain name of the iSNS node addition request to the discovery domain name  422  of the added record of the iSNS node information  420  ( 405 ).  
         [0135]     Next, the process of setting the VLAN (step  204  of  FIG. 4 ) will be described in detail.  
         [0136]     First, various information used for the process of setting the VLAN will be described.  
         [0137]     The network management server  111  stores VLAN group information and VLAN host information (these are shown in  FIG. 13  and  FIG. 14 ). The network management server  111  supplies such information according to a request from the storage connection management server  100  or the switch  122 . The network management server  111  communicates with the storage connection management server  100 , and the switch  122  by using the SNMP.  
         [0138]      FIG. 13  is a configuration diagram showing the VLAN group information stored in the network management server  111  of the embodiment of this invention.  
         [0139]     The VLAN group information  510  includes a VLAN_ID  511  which uniquely identifies a VLAN. In the second layer (data link layer) of the OSI reference model, by setting the VLAN_ID  511  in network devices, the network devices only of the same VLAN_ID  511  can communicate with each other.  
         [0140]      FIG. 14  is a configuration diagram showing the VLAN host information  520  stored in the network management server  111  of the embodiment of this invention.  
         [0141]     The VLAN host information  520  includes a MAC address  521  and a VLAN_ID  522 . One record of the VAN host information  520  is generated for each MAC address  521 . The VLAN_ID  522  is an identifier of a VLAN corresponding to the MAC address  521 .  
         [0142]     The primary storage system  116 , the external storage system  117 , and the computer  114  store an interface information shown in  FIG. 15 , and notify the information according to a request from the storage connection management server  100 . The primary storage system  116 , the external storage system  117 , and the computer  114  communicate with the storage connection management server  100  by using the SNMP.  
         [0143]      FIG. 15  is a configuration diagram showing the interface information  520  according to the embodiment of this invention.  
         [0144]     The interface information  520  is generated for each interface, and includes a MAC address  531  and an IP address  532 . The MAC address  531  is a MAC address of an interface of the device. The IP address  532  is an IP address of the interface of the device.  
         [0145]      FIG. 16  is a flowchart showing the process of setting the VLAN in step  204  of  FIG. 4 .  
         [0146]     First, the network setting program  109  obtains the VLAN group information  510  and the VLAN host information  520  from the network management server  111  ( 501 ).  
         [0147]     Next, the network setting program  109  extracts the setting type  221  from the changing request of the external connection  220 , and determines whether to set or release the external connection.  
         [0148]     When setting the external connection, the network setting program  109  creates a new VLAN_ID (3) different from the VLAN_ID  511  (1 and 2) contained in the obtained VLAN group information  510 . Then, the network setting program  109  adds and sets the created VLAN_ID (3) in the VLAN group information  510  ( 503 ).  
         [0149]     The network setting program  109  extracts the iSCSI name  222  (storage 1) from the changing request of the external connection  220 . The network setting program  109  obtains an IP address from the storage system of the extracted iSCSI name  222  (storage 1). Then, by referring to the interface information  530 , the network setting program  109  obtains a MAC address  531  in which the obtained IP address coincides with the IP address  532 .  
         [0150]     Then, the network setting program  109  sends a VLAN setting request. The VLAN setting request includes the obtained MAC address  531  and the created VLAN_ID (3) to the network management server  111 .  
         [0151]     The network management server  111  adds the MAC address  531  of the VLAN setting request to the MAC address  521  of the VLAN host information  520 . Further, the network management server  111  adds the VLAN_ID (3) of the VLAN setting request to the VLAN_ID  522  of the VLAN host information  520 .  
         [0152]     Next, the network setting program  109  extracts the Remote iSCSI name  224  (storage 2) from the changing request of the external connection  220 . For a portal of the “STORAGE 2”, the network setting program  109  adds a new VLAN_ID (3) to the VLAN host information as in the case of the “STORAGE 1” ( 504 ).  
         [0153]     On the other hand, when the external connection is released in step  502 , the network setting program  109  extracts the iSCSI name  222  from the changing request of the external connection. The network setting program  109  obtains the IP address from the primary storage system  116  of the iSCSI name  222 . Then, by referring to the interface information  530 , the network setting program  109  obtains the MAC address  531  in which the obtained IP address coincides with the IP address  532 .  
         [0154]     Then, the network setting program  109  extracts from the obtained VLAN host information  520 , the VLAN_ID  522  in which the obtained MAC address  531  coincides with the MAC address  521  of the VLAN host information  520 . This VLAN_ID  522  is a VLAN_ID set to the external connection portal of the primary storage system  116 .  
         [0155]     Next, the network setting program  109  extracts the Remote iSCSI name  224  from the changing request of the external connection  220 .  
         [0156]     The network setting program  109  obtains an IP address from the external storage system  117  which is the extracted Remote iSCSI name  224 . Then, by referring to the interface information  530 , the network setting program  109  obtains the MAC address  531  in which the obtained IP address coincides with the IP address  532 .  
         [0157]     Then, the network setting program  109  sends the VLAN setting request including the VLAN_ID set to external connection portal of the primary storage system  116 .  
         [0158]     Upon receiving of the VLAN setting request, the network management server  111  adds the MAC address of the VLAN setting request to the MAC address  531  of the VLAN host information  520 , and adds the VLAN_ID of the VLAN setting request to the VLAN_ID  522  of the VLAN host information  520 .  
         [0159]     Accordingly, the portal of the primary storage system  116  and the portal of the external storage system  117  belong to the same VLAN ( 505 ).  
         [0160]     According to the embodiment of this invention, the VLAN is set corresponding to the MAC address. However, a VLAN of the other system such as a port VLAN or a tagged VLAN may be set.  
         [0161]     Next, the process of changing the external connection state (step  205  of  FIG. 4 ) will be described in detail.  
         [0162]     First, various information used for the process of changing the external connection state will be described.  
         [0163]     The storage management server  112  stores the logical volume constitution information  150  as in the case of the storage connection management server  100 . The storage management server  112  notifies the information according to a request from the storage connection information  100 . Here, the storage management server  112  and the storage connection management server  100  communicate with each other by using the SNMP or the CIM.  
         [0164]     The agent  115  stores the volume information exemplified in  FIGS. 17A and 17B . The agent  115  notifies the information according to a request from the storage connection management server  100 . The agent  115  and the storage connection information  100  communicate with each other by using the SNMP.  
         [0165]      FIG. 17A  and  FIG. 17B  is a configuration diagram showing the volume information stored by the agent  115  of the embodiment of this invention.  FIG. 17A  shows the external connection before a change, and  FIG. 17B  shows the external connection after the change.  
         [0166]     The volume information  610  is generated for each logical volume managed by the agent  115 , and includes volume names  611 ,  614 , connection target iSCSI names  612 ,  615 , and LUNs  613 ,  616 .  
         [0167]     Each of the volume names  611  and  614  is an identifier by which a computer application identifies the logical volume. Each of the connection target iSCSI names  612 ,  615  is an iSCSI name of the iSCSI node of the storage system which has the logical volume. Each of the LUN&#39;s  613 ,  616  is a LUN of the logical volume.  
         [0168]      FIG. 18  is a configuration diagram showing an agent constitution information stored in the database of the embodiment of this invention.  
         [0169]     The agent constitution information  620  is stored in the database  106  of the storage connection management server  100 .  
         [0170]     The agent constitution information  620  is generated for each agent, and includes a host name  621 , an IP address  622 , a volume name  623 , a connection target iSCSI name  624 , and a LUN  625 .  
         [0171]     The host name  621  is an identifier of the computer  114  in which the agent  115  is operated. The IP address  622  is an IP address of the computer  114  in which the agent  115  is operated. The volume name  623  is an identifier by which the application of the computer  114  identifies the logical volume. The connection target iSCSI name  624  is an iSCSI name of the storage system which has the logical volume. The LUN  625  is an LUN of the logical volume.  
         [0172]      FIG. 19  is a flowchart showing the process of changing the external connection state in step  205  of  FIG. 4 .  
         [0173]     First, the external connection changing program  110  extracts the setting type  221  from the changing request of the external connection  220 , and determines whether to set or release the external connection.  
         [0174]     In the case of setting the external connection, the external connection changing program  110  sends information including the iSCSI name  222  of the changing request of the external connection  220 , the LUN  223 , the Remote iSCSI name  224 , and the Remote LUN  225  to the storage management server  112  ( 602 ).  
         [0175]     Upon receiving of the information, by referring to the logical volume constitution information  150 , the storage management server  112  compares the Remote iSCSI name  224  (storage 2) with the iSCSI name  151 . Further, the storage management server  112  compares the Remote LUN  225  (2) with the LUN  152 . Then, the storage management server  112  extracts the record of the logical volume constitution information  150  in which both of the iSCSI name and the LUN coincide with each other.  
         [0176]     The storage management server  112  changes the extracted record. Specifically, for the extracted record, the storage management server  112  changes the iSCSI name  151  to the iSCSI name  222  (storage 1) of the changing request of the external connection  220 , the LUN  152  to the LUN  223  (5) of the changing request of the external connection  220 , an external connection flag  154  to “1”, the Remote iSCSI name  155  to the Remote iSCSI name  224  (storage 2) of the changing request of the external connection  220 , and the Remote LUN  156  to the Remote LUN  225  (2) of the changing request of the external connection  220 .  
         [0177]     Next, by referring to the changing request of the external connection  220  and the agent constitution information  620 , the external connection changing program  110  obtains the host name  621  of the computer  114  which accesses the external storage system  121 . The external connection changing program  110  searches the agent  115  from the computer  114  of the obtained host name  621  ( 603 ).  
         [0178]     By referring to the agent constitution information  620 , the external connection changing program  110  compares the Remote iSCSI name  224  (storage 2) with the connection target iSCSI name  624 , and further compares the Remote LUN  225  (2) with the LUN  625 .  
         [0179]     Then, the external connection changing program  110  obtains one record of the agent constitution information  620  in which both of the connection iSCSI name and the LUN coincide with each other. For the obtained record of the agent constitution information  620 , the external connection changing program  110  changes the connection target iSCSI name  624  to the iSCSI name  222  (storage 1) of the changing request of the external connection  220 , and the LUN  625  to the LUN  223  (5) of the changing request of the external connection  220 .  
         [0180]     Next, the external connection changing program  110  collates the changing request of the external connection  220  with the volume information  610 . In detail, the external connection changing program  110  compares the Remote iSCSI name  224  (storage 2) with the connection target iSCSI name  611 , and the Remote LUN  225  (2) with the LUN  613 . Then, the external connection changing program  110  obtains a volume name  611  (volume 5) in which both of the iSCSI name and the LUN coincide with each other. The external connection changing program  110  sends a connection target changing request. The connection target changing request includes the obtained volume name  611  (volume 5), the iSCSI name  222  (storage 1) of the changing request of the external connection, and the LUN  223  (5) of the changing request of the external connection to the agent  115  ( 604 ).  
         [0181]     The agent  115  changes the volume information  610  according to the received connection target changing request. Specifically, the agent  115  extracts one record of the volume information  610  of the volume name  611  which coincides with the volume name (volume 5) of the connection target changing request. For the extracted record of the volume information  610 , the agent  115  changes the connection target iSCSI name  612  to the iSCSI name  222  (storage 1) of the connection target changing request, and the LUN  613  to the LUN (5) of the connection target changing request. By this process, the volume information  610  is changed from  FIG. 17A  to  FIG. 17B .  
         [0182]     On the other hand, in the case of releasing the external connection, the external connection changing program  110  collates the changing request of the external connection  220  with the agent constitution information  620 , compares the iSCSI name  222  with the connection target iSCSI name  624 , and further compares the LUN  223  with the LUN  625 . The external connection changing program  110  obtains one record of the agent constitution information  620  in which both of the iSCSI name and the LUN coincide with each other. The external connection changing program  110  searches the agent  115  from the computer  114  of the host name  621  contained in the obtained record ( 605 ).  
         [0183]     Moreover, for the obtained record of the agent constitution information  620 , the external connection changing program  110  changes the connection target iSCSI name  624  to the Remote iSCSI name  224  of the changing request of the external connection  220 , and the LUN  625  to the Remote LUN  225  of the changing request of the external connection  220 .  
         [0184]     Next, the external connection changing program  110  sends the connection target changing request to the searched agent  115  ( 606 ). The connection target changing request includes the volume name  623  contained in the obtained record of the agent constitution information  620 , the Remote iSCSI name  224  of the changing request of the external connection  220 , and the Remote LUN  225  of the changing request of the external connection  220 .  
         [0185]     The agent  115  that has received the connection target changing request changes the volume information  610  as in the case of the agent  115  that has received the connection target changing request in step  604  described above.  
         [0186]     Next, the external connection changing program  110  searches one record of the logical volume information  150  which coincides with the iSCSI name  222  of the changing request of the external connection  220 , the LUN  223 , the Remote iSCSI name  224 , and the Remote LUN  225 . Then, the external connection changing program  110  sends a request of deleting the searched record of the volume information  150  to the storage management server  112  ( 607 ).  
         [0187]     The storage management server  112  that has received the request deletes the one record from the volume information  150 .  
         [0188]     The embodiment of this invention has been described by way of example in which the process is carried out through the IP-SAN. However, this invention can be applied to a SAN comprising a Fiber Channel (FC) or a SAN comprising a mixture of an FC and an IP.  
         [0189]     While the present invention has been described in detail and pictorially in the accompanying drawings, the present invention is not limited to such detail but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims.