Abstract:
In a SAN where a zone has been set through hardware zoning, when any of devices connected to a fabric have been changed, the change is detected. Provided is a method for managing a devices in a Storage Area Network (SAN), each switch in the SAN comprising a memory and a plurality of ports that are connected to a computer and a storage subsystem, the method including obtaining a unique identifier from each of the computer and the storage subsystem connected to the ports, and storing the obtained identifier in the memory.

Description:
CLAIM OF PRIORITY  
       [0001]     The present application claims priority from Japanese application P2004-235389 filed on Aug. 12, 2004, the content of which is hereby incorporated by reference into this application.  
       BACKGROUND OF THE INVENTION  
       [0002]     This invention relates to a method for managing a devices in the Storage Area Network (SAN) (SAN is a network of storage and system components, all communicating on a Fibre Channel network), when any of devices connected to SAN have been changed (added or removed), system administrator detect the change, and restored. In particular, this invention relates to zoning of a SAN.  
         [0003]     Realized as one form of a SAN (Storage Area Network) is a SAN which is formed by a fabric having one or more Fibre Channel switches (FC-SWs). By using the fabric, it also becomes possible to form a large-scale SAN. In a SAN formed by such a fabric, when it is desired to limit nodes (hosts and storage subsystems connected to the fabric) that are capable of communicating with each other, zoning is performed. Once a zoning is specified, nodes belonging to the zone and nodes not belonging to the zone become incapable of accessing each other. As a result, it becomes possible to prevent access from unauthorized nodes and leakage of data to the unauthorized nodes.  
         [0004]     As to the zoning, there are hardware zoning and software zoning. The hardware zoning is also referred to as “port-based zoning”. The software zoning is also referred to as “WWN-based zoning”. With the hardware zoning, a zone is specified by designating the identifiers of physical ports on the switch. On the other hand, with the software zoning, a zone is specified by a port or node WWN (World Wide Name) (see W. Curtis Preston, “Using SANs &amp; NAS”, O&#39;Reilly &amp; Associates, Inc., February, 2002, pp. 48 through 50, for instance). The port WWN is also referred to as “WWPN (World Wide Port Name)”. In general, the hardware zoning is adopted because its operation is easy.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005]     With the hardware zoning, a zone is specified by the switch domain and port number. When devices (hosts and storage subsystems) are connected to the ports belonging to the zone, the devices belong to the zone. With the hardware zoning, even when any of the devices connected to the ports have been changed (“changed” means disconnected or other device is connected to the port), no influence is exerted on the zoning itself. Therefore, there is a case where even when any of the devices connected to the ports have been changed (“changed” means disconnected or other device is connected to the port) erroneously, a system administrator does not notice the change and continues operation of a system. Also, even when the system administrator notices the change, it is impossible for him/her to determine the devices connected before the change. Accordingly, it is impossible for the system administrator to restore an original connection.  
         [0006]     According to this invention, there is provided a method for managing a devices in a Storage Area Network (SAN), each switch in the SAN comprising a memory and a plurality of ports that are connected to the computer and the storage subsystem, the method including: obtaining a unique identifier from each of the computer and the storage subsystem connected to the ports; and storing the obtained identifier in the memory.  
         [0007]     According to this invention, unique identifiers obtained from nodes connected to ports are continuously stored even when the nodes connected to the ports have been changed. Therefore, when any of the devices connected to the ports constructing a zone have been changed, it is possible to detect the change while adopting the hardware zoning. As a result, it becomes possible for a system administrator to know the device change by receiving a notification while operating a system with ease like in the case of the hardware zoning. In addition, it becomes possible for the system administrator to restore a connection before the change. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a block diagram of a computer system according to an embodiment of this invention.  
         [0009]      FIG. 2  is an explanatory diagram of the contents of a memory of an FC-SW according to the embodiment of this invention.  
         [0010]      FIG. 3  is an explanatory diagram of a zone management table according to the embodiment of this invention.  
         [0011]      FIG. 4  is an explanatory diagram of an alias management table according to the embodiment of this invention.  
         [0012]      FIG. 5  is an explanatory diagram of a port management table according to the embodiment of this invention.  
         [0013]      FIG. 6  is an explanatory diagram of a WWPN management table according to the embodiment of this invention.  
         [0014]      FIG. 7  is an explanatory diagram of an alias-port mapping table according to the embodiment of this invention.  
         [0015]      FIG. 8  is an explanatory diagram of a zone-alias mapping table according to the embodiment of this invention.  
         [0016]      FIG. 9  is an explanatory diagram of a port list-display screen displayed on a display screen of a management terminal according to the embodiment of this invention.  
         [0017]      FIG. 10  is an explanatory diagram of a zone list-display screen displayed on the display screen of a management terminal according to the embodiment of this invention.  
         [0018]      FIG. 11  is a flowchart of lock request processing of an FC-SW management program according to the embodiment of this invention.  
         [0019]      FIG. 12  is a flowchart of lock release processing of the FC-SW management program according to the embodiment of this invention.  
         [0020]      FIG. 13  is a flowchart of port management table update processing of the FC-SW management program according to the embodiment of this invention.  
         [0021]      FIG. 14  is a flowchart of zone management table update processing of the FC-SW management program according to the embodiment of this invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     An embodiment of this invention will now be described with reference to the accompanying drawings.  
         [0023]      FIG. 1  is a block diagram of a computer system according to the embodiment of this invention.  
         [0024]     The computer system shown in  FIG. 1  includes hosts  101 , storage subsystems  102 , Fibre Channel switches (FC-SWs)  103 , and a management terminal  105 . The hosts  101  are communicably connected to the storage subsystems  102  by the FC-SWs  103  and Fibre Channel (FC) cables  104 . The two FC-SWs  103  are communicably connected to each other by an FC cable  104 . The management terminal  105  is communicably connected to the FC-SWs through a LAN  106 .  
         [0025]     The FC-SWs  103  and the FC cables  104  form a Storage Area Network (SAN) that communicably connects the hosts  101  and the storage subsystems  102  to each other.  
         [0026]     Each host  101  includes at least a CPU (not shown), a memory (not shown), and a host bus adapter (HBA)  107 . The HBA  107  is an interface that communicates with the storage subsystems through the FC-SWs  103 , and includes ports  110  to which the FC cables  104  are connected. The CPU accesses the storage subsystems  102  through the ports  110  of the HBA  107  by executing an application program stored in the memory.  
         [0027]     Each storage subsystem  102  is a disk array system formed of plural disk drives, for instance. The storage subsystem  102  includes ports  111  to which the FC cables  104  are connected and which communicate with the hosts  101  through the FC-SWs  103 .  
         [0028]     Each FC-SW  103  includes at least a CPU  108  that controls the FC-SW  103 , a memory  109 , and plural ports  112 . As will be described later, an FC-SW management program and various tables are stored in the memory  109 . In the memory  109 , the e-mail address of a system administrator may also be stored. The CPU  108  is capable of setting connections between arbitrary plural ports  112  by executing the FC-SW management program.  
         [0029]     The management terminal  105  is a computer including at least a CPU (not shown), a memory (not shown), an input device (not shown), and a display screen  113 . The system administrator manages the FC-SWs  103  using the management terminal  105 . The system administrator accesses the FC-SW management program through the LAN  106  to manage the FC-SWs  103 . Alternatively, the system administrator may access the FC-SW management program through a telnet connection from the management terminal  105 . As will be described later, information concerning the FC-SWs  103  is displayed on the display screen  113  of the management terminal  105 .  
         [0030]     It should be noted that one or more FC-SWs that are communicably connected to each other form a fabric. In  FIG. 1 , the two FC-SWs  103  that are communicably connected to each other by the FC cable  104  form one fabric.  
         [0031]     Also, each device (such as the host  101  or the storage subsystem  102 ) connected to a port  112  of the fabric is also called the node.  
         [0032]     It is possible for the system administrator to arbitrarily set a zone in the fabric. The zone is a logical group set in the fabric. Each node belonging to the zone is capable of communicating with other nodes belonging to the same zone but is incapable of communicating with nodes not belonging to the zone.  
         [0033]     Next, the outline of this invention will be described with reference to  FIG. 1 .  
         [0034]     In this embodiment, the system administrator sets a zone by designating the identifiers of the ports  112  of the fabric. In addition, it is possible for the system administrator to “lock” arbitrary ports  112 . At this time, the World Wide Port Names (WWPNs) of the ports  110  and/or  111  of the devices (hosts  101  and/or storage subsystems  102 ) connected to the locked ports  112  are stored in the memory  109 . Further, current time instants of each of WWPNs may be stored in the memory  109  associated with WWPNs.  
         [0035]     Here, each WWPN is a unique identifier that uniquely identifies a port on a worldwide basis, is set for the port by a device manufacture, and will never be altered. Accordingly, there will never occur a situation where plural ports have the same WWPN.  
         [0036]     It should be noted that in this embodiment, each device is identified using the WWPN as its unique identifier, although another unique identifier (World Wide Node Name (WWNN), for instance) may be used instead.  
         [0037]     When any of the devices connected to the locked ports  112  have been changed to other devices, this results in a situation where some of the WWPNs stored as to the ports  112  in the memory  109  do not agree with the WWPNs of the ports  110  and/or  111  actually connected to the ports  112 . The FC-SWs  103  compare these WWPNs and, when they do not agree with each other, judge that the device connection has been changed and issue a notification to the system administrator. WWPNs of the changed device and current time instant may be stored in the memory  109 .  
         [0038]     It is possible for the system administrator to know that the device connection in the zone has been changed by receiving this notification.  
         [0039]     Also, when judging that a problem exists in the informed change (for instance, when the device connection has been changed without authorization), it is possible for the system administrator to take a countermeasure. For instance, the system administrator stops communication between each unauthorized device and other devices in the zone, to which the device belongs, or stops overall operation of the system. Further, it is possible for the system administrator to restore an original connection by referring to the WWPNs stored in the memory  109 .  
         [0040]     On the other hand, when judging that no problem exists in the informed change (when device connection has been temporarily changed due to device failure, for instance), it is possible for the system administrator to continue the operation of the system without any stops.  
         [0041]     Also, when it is judged that the device connection has been changed, the FC-SW  103  may automatically stop communication between each device that is newly connected and other devices in the zone to which the device belongs.  
         [0042]     Next, this invention will be described in detail.  
         [0043]      FIG. 2  is an explanatory diagram of the contents of the memory  109  of each FC-SW  103  according to the embodiment of this invention.  
         [0044]     In the memory  109 , at least an FC-SW management program  201 , a zone management table  202 , an alias management table  203 , a port management table  204 , a World Wide Port Name (WWPN) management table  205 , an alias-port mapping table  206 , and a zone-alias mapping table  207  are stored.  
         [0045]     The FC-SW management program  201  is a program executed by the CPU  108  and manages the operation of the FC-SW  103 . Processing contained in the FC-SW management program  201  will be described in detail later with reference to  FIGS. 11 through 14 .  
         [0046]     In each of the tables  202  through  207 , information necessary to manage the FC-SW  103  is recorded.  
         [0047]     In the tables  202  through  207  of each of the FC-SWs  103  forming one fabric, the same values are stored. When a value stored in a table of one of the FC-SWs  103  is changed, the changed value is reflected in a corresponding table of the other of the FC-SWs  103  through the LAN  106  or the FC cable  104 .  
         [0048]     The contents of the tables  202  through  207  will be described in detail below with reference to  FIGS. 3 through 8 .  
         [0049]      FIG. 3  is an explanatory diagram of the zone management table  202  according to the embodiment of this invention.  
         [0050]     In this embodiment, at least one zone is set by designating the port numbers of the ports  112  of the fabric. The correspondences between the zone and the ports  112  forming the zone are specified by the zone-alias mapping table  207  shown in  FIG. 8  and the alias-port mapping table  206  shown in  FIG. 7 , as will be described later.  
         [0051]     The zone management table  202  shown in  FIG. 3  is a table for managing the state of each zone set in the fabric.  
         [0052]     Each zone ID  301  is the unique identifier of a zone set in the fabric.  
         [0053]     Each zone name  302  is the name of a zone set in the fabric. This zone name  302  is set in order to facilitate system management. It is possible for the system administrator to arbitrarily set the zone name  302  unless the same zone name  302  is set for different zones.  
         [0054]     Each zone state  303  is a flag showing the state of a zone. When the zone state  303  is set to “0”, this indicates that the zone is under a normal state. On the other hand, when the zone state  303  is set to “1”, this indicates that the zone is under an abnormal state. Here, the abnormal state refers to a state where at least one of the ports  112  belonging to the zone is locked and the device connected to the locked port  112  has been changed.  
         [0055]     The zone state  303  is set and updated by zone management table update processing shown in  FIG. 14  of the FC-SW management program  201 .  
         [0056]     In this embodiment, as shown in  FIG. 3 , three zones are set in the fabric and a zone “karahuto_kaji” among these zones is abnormal.  
         [0057]      FIG. 4  is an explanatory diagram of the alias management table  203  according to the embodiment of this invention.  
         [0058]     Each alias is a group composed of one or more ports  112  in the fabric. The alias is set in order to facilitate system management. The operation of the system is possible even when the alias is not set. However, when the alias is set, it becomes possible to give a name that is easy to understand intuitively (name or the like of the device connected to a port  112 , for instance) to one port  112  or a group of ports  112 , so the efficiency of system management improves.  
         [0059]     The alias management table  203  is a table that manages each alias set in the fabric.  
         [0060]     Each alias ID  401  is the unique identifier of an alias set in the fabric.  
         [0061]     Each alias name  402  is the name of an alias. It is possible for the system administrator to arbitrarily set the alias name  402  unless the same alias name  402  is set for different aliases.  
         [0062]     In this embodiment, as shown in  FIG. 4 , two aliases are set in the fabric.  
         [0063]      FIG. 5  is an explanatory diagram of the port management table  204  according to the embodiment of this invention.  
         [0064]     The port management table  204  is a table that manages each port  112  existing in the fabric. In the port management table  204 , information about every port  112  existing in the fabric is stored. In  FIG. 5 , however, for ease of explanation, only information about three ports  112  is illustrated and information about other ports  112  is omitted.  
         [0065]     In the port management table  204 , each port ID  501  is the unique identifier of a port  112  belonging to the fabric.  
         [0066]     Each domain ID  502  is the unique identifier of the FC-SW  103  to which a port  112  belongs.  
         [0067]     Each port number  503  is the number with which a port  112  is uniquely identified in the domain (in other words, FC-SW  103 ) to which the port  112  belongs.  
         [0068]     For instance, a port, whose port ID  501  is “0x50”, is the “0”th port of the FC-SW  103  whose domain ID  502  is “5”.  
         [0069]     Each lock flag  504  is a flag showing whether a port  112  is locked. When the port  112  is locked, the value of the lock flag  504  is set to “1” (true). On the other hand, when the port  112  is not locked, the value of the lock flag  504  is set to “0” (false). The value of the lock flag  504  is set and updated by lock request processing shown in  FIG. 11  and lock release processing shown in  FIG. 12  of the FC-SW management program  201 .  
         [0070]     Each WWPN consistency  505  is a flag showing whether the value of the identifier of the WWPN stored as to a locked port  112  in the memory  109  (in other words, the value of a lock WWPNID  507  to be described later) agree with the value of the identifier of the WWPN actually connected to the port (in other words, the value of a connection destination WWPNID  506  to be described later). When they agree with each other, the value of the WWPN consistency  505  is set to “0”. On the other hand, when they do not agree with each other, the value of the WWPN consistency  505  is set to 1”. The value of the WWPN consistency  505  is set and updated by port management table update processing shown in  FIG. 13  of the FC-SW management program  201 .  
         [0071]     It should be noted that the value of the WWPN consistency  505  of each port  112 , whose lock flag  504  is set to “0”, is set blank because the port is not locked.  
         [0072]     Each connection destination WWPNID  506  is the unique identifier shown in  FIG. 6  of the WWPN of the port  110  or  111  of the device actually connected to a port  112 . The value of the connection destination WWPNID  506  is set and updated by the port management table update processing shown in  FIG. 13  of the FC-SW management program  201 .  
         [0073]     Each lock WWPNID  507  is the unique identifier shown in  FIG. 6  of the WWPN of the port  110  or  111  of the device connected to a locked port  112  at a point in time when the port was locked. The value of the lock WWPNID  507  is set and updated by the lock request processing shown in  FIG. 11  and the lock release processing shown in  FIG. 12  of the FC-SW management program  201 .  
         [0074]     It should be noted that the value of the lock WWPNID  507  of each port  112 , whose lock flag  504  is set to “0”, is set blank because the port is not locked.  
         [0075]     In  FIG. 5 , a port “0x51” is locked and its values of the connection destination WWPNID  506  and the lock WWPNID  507  do not agree with each other. Therefore, the value of the WWPN consistency  505  of the port “0x51” is set to “1”. In other words, it is indicated that the device connected to the port “0x51” has been changed after the locking of the port “0x51”.  
         [0076]      FIG. 6  is an explanatory diagram of the WWPN management table  205  according to the embodiment of this invention.  
         [0077]     In the WWPN management table  205 , each WWPNID  601  is the unique identifier of a port  110  or  111  that is connected to the fabric (or was previously connected thereto). The WWPNID  601  is automatically set by the FC-SW management program  201 .  
         [0078]     Each WWPN  602  is the WWPN of a port  110  or  111  that is connected to the fabric (or was previously connected thereto).  
         [0079]      FIG. 7  is an explanatory diagram of the alias-port mapping table  206  according to the embodiment of this invention.  
         [0080]     The alias-port mapping table  206  is a table showing the correspondences between the aliases set in the fabric and the ports  112  belonging to the aliases.  
         [0081]     In the alias-port mapping table  206 , each alias ID  701  is the unique identifier of an alias set in the fabric and corresponds to the alias ID  401  of the alias management table  203 .  
         [0082]     Each port ID  702  is the identifier of a port  112  belonging to an alias and corresponds to the port ID  501  of the port management table  204 .  
         [0083]     In the example shown in  FIG. 7 , ports “0x50” and “0x51” belong to an alias “0” set in the fabric according to this embodiment and a port “0x52” belongs to an alias “1” in the fabric.  
         [0084]      FIG. 8  is an explanatory diagram of the zone-alias mapping table  207  according to the embodiment of this invention.  
         [0085]     The zone-alias mapping table  207  is a table showing the correspondences between the zones set in the fabric and the aliases set in the zones.  
         [0086]     In the zone-alias mapping table  207 ; each zone ID  801  is the unique identifier of a zone set in the fabric and corresponds to the zone ID  301  of the zone management table  202 .  
         [0087]     Each alias ID  802  is the unique identifier of an alias set in a zone and corresponds to the alias ID  401  of the alias management table  203 .  
         [0088]     In the example shown in  FIG. 8 , aliases “0” and “1” are set in a zone “0” according to this embodiment.  
         [0089]     Ultimately, when  FIGS. 3 through 8  are summarized, the port “0” (port “0x50”) of the domain (in other words, the FC-SW  103 ) “5” forming the fabric according to this embodiment forms the alias “0”, as can be seen from  FIGS. 5 and 7 . Also, the name of the alias “0” is “karahuto”, as shown in  FIG. 4 .  
         [0090]     On the other hand, the ports “1” and “2” (ports “0x51” and “0x52”) of the domain “5” form the alias “1”, as can bee seen from  FIGS. 5 and 7 . Also, the name of the alias “1” is “RAID 450_CL1_C”, as shown in  FIG. 4 .  
         [0091]     The ports “0x50”, “0x51”, and “0x52” form the zone “0”, as can be seen from  FIGS. 7 and 8 . Also, the name of the zone “0” is “karahuto_kaji”, as shown in  FIG. 3 .  
         [0092]     The port “0x51” is locked and the device connected thereto has been changed, as can be seen from  FIG. 5 . Accordingly, the zone state  303  of the zone “0” is set to “1” (in other words, abnormal), as shown in  FIG. 3 .  
         [0093]     In the fabric according to this embodiment, zones “1” and “2” are further set, as shown in  FIG. 3 . Also, the names of the zones are respectively “alaska_nomura” and “nahotoka_enmei”.  
         [0094]     Next, contents displayed on the display screen  113  of the management terminal  105  when the system is under the state described above will be described with reference to  FIGS. 9 and 10 .  
         [0095]      FIG. 9  is an explanatory diagram of a port list-display screen displayed on the display screen  113  of the management terminal  105  according to the embodiment of this invention.  
         [0096]     A port list-display screen  900  is composed of a domain display area  901  and a port display area  902 .  
         [0097]     In the domain display area  901 , every FC-SW  103  forming the fabric is list-displayed. In the example shown in  FIG. 9 , the fabric is formed by the two FC-SWs  103 .  
         [0098]     In the port display area  902 , every port  112  forming an FC-SW  103  designated in the domain display area  901  is list-displayed. In the example shown in  FIG. 9 , the ports  112  forming the FC-SW “greenland” (domain “5”) are displayed.  
         [0099]     Each port number  903  is the number that uniquely identifies a port  112  in the FC-SW (domain) and corresponds to the port number  503  of the port management table.  
         [0100]     Each lock state  904  indicates whether a port is locked. When the port is locked, the lock state  904  also indicates whether its connection has been changed. In the example shown in  FIG. 9 , the port “0” is locked and its connection is not changed. Therefore, on line  906 , as the lock state  904  of the port “0”, a word “LOCKED” and a figure of a padlock are displayed. The port “1” is locked and its connection has been changed. Therefore, on line  907 , as the lock state  904  of the port “1”, words “BROKEN” and a figure where a sign “x” is superimposed on the padlock figure are displayed. The port “2” is not locked. Therefore, on line  909 , the lock state  904  of the port “2” is set blank.  
         [0101]     It should be noted that the padlock figure is displayed in order to allow the system administrator to intuitively grasp the lock state. Accordingly, there occurs no problem even when another figure is used or no figure is displayed.  
         [0102]     Each connection destination WWPN  905  indicates the WWPN of the device connected to a port  112 . This connection destination WWPN  905  corresponds to the WWPN  602  shown in  FIG. 6 . In the example shown in  FIG. 9 , the connection of the port “1” has been changed. A WWPN “21:01:00:e0:8b:08:10:9a” on line  907  indicates the WWPN of the device that was connected to the port “1” when this port was locked, while a WWPN “21:01:00:e0:8b:08:c9:19” on line  908  indicates the WWPN of the device that is currently connected to the port “1”.  
         [0103]     It is possible for the system administrator to know that the connection of the locked port “1” has been changed by viewing the words “no lock destination” displayed as the lock state  904  on the display screen  113  of the management terminal  105 . In addition, it is possible for the system administrator to know the WWPN of the device that was connected to the port “1” at a point in time when the port was locked by viewing the connection destination WWPN  905 . Accordingly, it becomes possible for the system administrator to return the connection of the port “1” to a state at the point in time when the port was locked.  
         [0104]      FIG. 10  is an explanatory diagram of a zone list-display screen displayed on the display screen  113  of the management terminal  105  according to the embodiment of this invention.  
         [0105]     A zone list-display screen  1000  is composed of a zone list-display area  1001 .  
         [0106]     In a zone name column  1002  of the zone list display area  1001 , the name of each zone set in the fabric is list-displayed. The zone name displayed in the zone name column  1002  corresponds to the zone name  302  of the zone management table  202 .  
         [0107]     In a zone state column  1003 , the state of each zone is displayed. The zone state displayed in the zone state column  1003  corresponds to the zone state  303  of the zone management table  202 . The zone state  303  of the zone “karahuto_kaji” is “1” (in other words, abnormal), as shown in  FIG. 3 . Therefore, a word “CONNECTION ERROR” is displayed in the zone state column  1003  for the zone “karahuto_kaji”.  
         [0108]     It is possible for the system administrator to know that the state of the zone “karahuto_kaji” is abnormal by viewing the word “CONNECTION ERROR” in the zone state column  1003  displayed on the display screen  113  of the management terminal  105 . In other words, it is possible for the system administrator to know that any of the connections of the locked ports  112  belonging to the zone “karahuto_kaji” have been changed.  
         [0109]     Next, processing of the FC-SW management program  201  will be described with reference to flowcharts.  
         [0110]      FIG. 11  is a flowchart of the lock request processing of the FC-SW management program  201  according to the embodiment of this invention.  
         [0111]     First, in a step  1101 , the system administrator issues a lock request for one of the ports  112 , thereby starting the lock request processing. Here, the port designated by the lock request issued by the system administrator is set as the port A.  
         [0112]     It is possible for the system administrator to issue the lock request by manipulating the port list-display screen  900  displayed on the management terminal  105 . For instance, the system administrator may issue the lock request by manipulating the port number  903  of the port A displayed in the port display area  902  with a mouse or the like.  
         [0113]     Alternatively, the system administrator may issue the lock request by inputting a command into the management terminal  105 .  
         [0114]     Next, in a step  1102 , a record corresponding to the port A is read from the port management table  204  and is set as the record A. Here, the record is one line of the port management table  204 .  
         [0115]     Next, in a step  1103 , it is judged whether the value of the lock flag  504  of the record A is “0”. When the value of the lock flag  504  of the record A is not “0”, the port A is already locked, so the processing ends.  
         [0116]     On the other hand, when the value of the lock flag  504  of the record A is “0”, the port A is not yet locked. Therefore, next, in a step  1104 , the value of the lock flag  504  of the record A is set to “1”.  
         [0117]     Next, in a step  1105 , the value of the connection destination WWPNID  506  of the record A is copied to the lock WWPNID  507  of the record A.  
         [0118]     Next, in a step  1106 , the word “LOCKED” and the padlock figure are displayed as the lock state  904  corresponding to the port A in the port display area  902  of the port list-display screen  900 .  
         [0119]     Then, the lock request processing ends.  
         [0120]     It should be noted that it is also possible for the system administrator to register his/her e-mail address during the lock request processing (in the step  1101 , for instance). In this case, the e-mail address is registered in the memory  109 . The registered e-mail address is used as the destination of a notification issued in a step  1319  of  FIG. 13  when any of the devices connected to the ports  112  have been changed or a notification issued in a step  1420  of  FIG. 14  when any of the states of the zones become abnormal.  
         [0121]      FIG. 12  is a flowchart of the lock release processing of the FC-SW management program  201  according to the embodiment of this invention.  
         [0122]     First, in a step  1201 , the system administrator issues a lock release request for one of the ports  112 , thereby starting the lock release processing. Here, the port designated by the lock release request issued by the system administrator is set as the port A.  
         [0123]     It is possible for the system administrator to issue the lock release in the same manner as the case of issuing the lock request.  
         [0124]     Next, in a step  1202 , a record corresponding to the port A is read from the port management table  204  and is set as the record A.  
         [0125]     Next, in a step  1203 , it is judged whether the value of the lock flag  504  of the record A is “1”. When the value of the lock flag  504  of the record A is not “1”, the port A is not yet locked, so the processing ends.  
         [0126]     On the other hand, when the value of the lock flag  504  of the record A is “1”, the port A is locked. Therefore, next, in a step  1204 , the value of the lock flag  504  of the record A is set to “0”.  
         [0127]     Next, in a step  1205 , the display of the word “LOCKED” and the padlock figure is deleted from the lock state  904  corresponding to the port A in the port display area  902  of the port list-display screen  900 , which is then set as blank.  
         [0128]     Then, the lock release processing ends.  
         [0129]      FIG. 13  is a flowchart of the port management table update processing of the FC-SW management program  201  according to the embodiment of this invention.  
         [0130]     First, the outline of the port management table update processing will be described.  
         [0131]     In the port management table update processing, first, in steps  1301  through  1313 , the connection destination WWPNID  506  corresponding to each port  112  in the port management table  204  is updated according to the WWPN of the device actually connected to the port  112 . Since, the WWPN is not contained in the port management table  204 , the WWPN management table  205  is referred to as necessary. Next, in steps  1314  through  1319 , when the port  112  is locked, it is judged whether its device connection has been changed and, when a result of this judgment is affirmative, a notification showing the change is issued to the administrator.  
         [0132]     Next, a procedure of the port management table update processing will be described in detail.  
         [0133]     After the port management table update processing starts, first, in the step  1301 , the first record of the port management table  204  is read and is set as the record A.  
         [0134]     Next, in the step  1302 , the WWPN of the device connected to the port  112  corresponding to the record A (in other words, the device connected to the port  112  corresponding to the domain ID  502  and the port number  503  of the record A) is obtained.  
         [0135]     Next, the connection destination WWPNID  506  of the record A is updated according to the WWPN obtained in the step  1302 . To do so, first, in the step  1303 , the first record of the WWPN management table  205  is read and is set as the record B.  
         [0136]     Next, in the step  1304 , it is judged whether the connection destination WWPNID  506  of the record A and the WWPNID  601  of the record B agree with each other. When they do not agree with each other, the WWPN  602  of the record B is not the WWPN corresponding to the connection destination WWPNID  506  of the record A. Therefore, in the step  1305 , a record next to the record B is read from the WWPN management table  205  and is set as a new record B. Then, the processing returns to the step  1304 .  
         [0137]     On the other hand, when the connection destination WWPNID  506  of the record A and the WWPNID  601  of the record B agree with each other, the WWPN  602  of the record B is the WWPN corresponding to the connection destination WWPNID  506  of the record A. Therefore, next, in the step  1306 , it is judged whether the WWPN  602  of the record B and the WWPN obtained in the step  1302  agree with each other. When they agree with each other, the device connected to the port  112  corresponding to the record A is not changed, so it is not required to update the connection destination WWPNID  506  of the record A. Therefore, in order to perform the processing for the next record A, the processing proceeds to a step  1320 .  
         [0138]     On the other hand, when the WWPN  602  of the record B and the WWPN obtained in the step  1302  do not agree with each other, the device connected to the port  112  corresponding to the record A has been changed. Accordingly, it is required to update the connection destination WWPNID  506  of the record A to a value corresponding to the WWPN obtained in the step  1302 . Therefore, next, in the step  1307 , the first record of the WWPN management table  205  is read and is set as the record B.  
         [0139]     Next, in the step  1308 , it is judged whether the WWPN  602  of the record B and the WWPN obtained in the step  1302  agree with each other. When they agree with each other, the WWPN  602  of the record B is the WWPN corresponding to the connection destination WWPNID  506  of the record A. Therefore, next, in the step  1313 , the WWPNID  601  of the record B is copied to the connection destination WWPNID  506  of the record A. As a result, the connection destination WWPNID  506  of the record A is updated according to the WWPN of the device actually connected.  
         [0140]     On the other hand, when the WWPN  602  of the record B and the WWPN obtained in the step  1302  do not agree with each other, the WWPN  602  of the record B is not the WWPN corresponding to the connection destination WWPNID  506  of the record A. Therefore, next, in the step  1309 , it is judged whether the record B is the last record of the WWPN management table  205 .  
         [0141]     When the record B is not the last record of the WWPN management table  205 , the processing proceeds to the step  1310  in which a record next to the record B is read from the WWPN management table  205  and is set as a new record B. Then, the processing returns to the step  1308 .  
         [0142]     On the other hand, when the record B is the last record of the WWPN management table  205 , the WWPN obtained in the step  1302  is not yet registered in the WWPN management table  205 . Therefore, in the step  1311 , the WWPN obtained in the step  1302  is additionally registered in the WWPN management table  205 .  
         [0143]     Next, in the step  1312 , the record added in the step  1311  is set as the record B. Then, the processing proceeds to the step  1313 .  
         [0144]     Next, in the step  1314 , it is judged whether the lock flag  504  of the record A is “1”.  
         [0145]     When the lock flag  504  of the record A is “0”, the port  112  corresponding to the record A is not locked, so the processing proceeds to the step  1320 .  
         [0146]     On the other hand, when the lock flag  504  of the record A is “1”, the port  112  corresponding to the record A is locked. Therefore, next, in the step  1315 , it is judged whether the connection destination WWPNID  506  and the lock WWPNID  507  of the record A agree with each other.  
         [0147]     When the connection destination WWPNID  506  and the lock WWPNID  507  of the record A agree with each other, the device connected to the port  112  corresponding to the record A is not changed. Therefore, in the step  1316 , the value of the WWPN consistency  505  of the record A is set to “0”. Then, the processing proceeds to the step  1320 .  
         [0148]     On the other hand, when the connection destination WWPNID  506  and the lock WWPNID  507  of the record A do not agree with each other, the device connected to the port  112  corresponding to the record A has been changed. Therefore, in the step  1317 , the value of the WWPN consistency  505  of the record A is set to “1”.  
         [0149]     It should be noted that a result of the operation in the step  1317  is reflected in the port list-display screen  900  displayed on the display screen  113  of the management terminal  105  through the LAN  106 . In other words, as the lock state  904  corresponding to the port  112  whose value of the WWPN consistency  505  has been changed to “1”, the words “BROKEN” and the figure where the sign “x” is superimposed on the padlock figure are displayed.  
         [0150]     Next, in the step  1318 , it is judged whether the e-mail address of the system administrator is registered in the memory  109 . It is possible for the system administrator to register his/her e-mail address in the memory  109  in advance. Alternatively, the system administrator may register his/her e-mail address at the time of issuing the lock request for the port  112  as shown in  FIG. 11 . When the e-mail address of the system administrator is not registered in the memory  109 , the processing proceeds to the step  1320 .  
         [0151]     On the other hand, when the e-mail address of the system administrator is registered in the memory  109 , an e-mail is transmitted to the address in the step  1319 , thereby issuing a notification showing that the device connected to the port  112  corresponding to the record A has been changed to the system administrator.  
         [0152]     It is possible for the system administrator to know that the device connected to the port  112  corresponding to the record A has been changed by receiving this e-mail. The e-mail contains every piece of information of the record A of the port management table  204  and information in the WWPN management table  205 , for instance. In this case, it becomes possible for the system administrator to know the identifier of the port  112  whose connection has been changed, the WWPN of the device that was connected before the change, and the WWPN of the device that is currently connected. In other words, it becomes possible for the system administrator to identify the device that was connected to the port  112  at a point in time when the port was locked and to restore an original connection.  
         [0153]     It should be noted that the value of the lock WWPNID  507  of the record A is held in the memory  109  until the lock of the port is released by the lock release processing shown in  FIG. 12 .  
         [0154]     Next, in the step  1320 , it is judged whether the record A is the last record of the port management table  204 .  
         [0155]     When the record A is not the last record, the update of every record of the port management table  204  is not yet completed. Therefore, in a step  1321 , a record next to the record A is read from the port management table  204  and is set as a new record A. Then, the processing returns to the step  1302 .  
         [0156]     On the other hand, when the record A is the last record, the update of every record of the port management table  204  is completed. Therefore, the port management table update processing ends.  
         [0157]     It is possible for the system administrator to execute the port management table update processing at an arbitrary point in time. Alternatively, the port management table update processing may be periodically executed at predetermined intervals (at intervals of several minutes, one hour, one day, or the like, for instance). When doing so, the port management table update processing updates the value of each required connection destination WWPNID  506  but does not update the value of its corresponding lock WWPNID  507 . For instance, assuming that the port management table update processing is executed at intervals of five minutes, when any of the devices connected to the ports  112  have been changed, this change is reflected in the values of the connection destination WWPNIDs  506  corresponding to the ports  112  within five minutes. On the other hand, even when any of the connected devices have been changed, the values of the lock WWPNIDs  507  corresponding to the ports  112  are not changed unless their lock is released by the lock release processing shown in  FIG. 12 .  
         [0158]     It should be noted that in the port management table update processing shown in  FIG. 13 , the device connection change judgment may be made only for the locked ports  112 . When any of the devices connected to the locked ports  112  have been changed, a notification showing the change is issued to the administrator. In this case, in the step  1301 , a record, whose lock flag  504  is “1”, of the port management table  204  is read and is set as the record A. Also, the judgment in the step  1314  is not made and the step  1315  is executed after the step  1313 . Further, in the step  1321 , the next record, whose lock flag  504  is “1”, is read and is set as a new record A. Then, the processing returns to the step  1302 .  
         [0159]     In this case, when the port list-display screen  900  shown in  FIG. 9  is to be displayed in order to execute the lock request processing shown in  FIG. 11 , it is required to obtain the WWPNs of the devices connected to the ports  112 .  
         [0160]      FIG. 14  is a flowchart of the zone management table update processing of the FC-SW management program  201  according to the embodiment of this invention.  
         [0161]     After the zone management table update processing is started, first, in a step  1401 , the first record of the zone management table  202  is read and is set as the record A.  
         [0162]     Next, in a step  1402 , the first record of the zone-alias mapping table  207  is read and is set as the record B.  
         [0163]     Next, in a step  1403 , it is judged whether the zone ID  301  of the record A and the zone ID  801  of the record B agree with each other. When they do not agree with each other, the alias ID  802  of the record B does not belong to the zone corresponding to the record A. In this case, the processing proceeds to a step  1415 .  
         [0164]     On the other hand, when the zone ID  301  of the record A and the zone ID  801  of the record B agree with each other, the alias ID  802  of the record B belongs to the zone corresponding to the record A. Therefore, next, in a step  1404 , the first record of the alias-port mapping table  206  is read and is set as the record C.  
         [0165]     Next, in a step  1405 , it is judged whether the alias ID  802  of the record B and the alias ID  701  of the record C agree with each other. When they do not agree with each other, the port ID  702  of the record C does not belong to the alias corresponding to the record B. In this case, the processing proceeds to a step  1413 .  
         [0166]     On the other hand, when the alias ID  802  of the record B and the alias ID  701  of the record C agree with each other, the port ID  702  of the record C belongs to the alias corresponding to the record B. In other words, the port ID  702  of the record C belongs to the zone corresponding to the record A. Therefore, next, in a step  1406 , the first record of the port management table  204  is read and is set as the record D.  
         [0167]     Next, in a step  1407 , it is judged whether the port ID  702  of the record C and the port ID  501  of the record D agree with each other. When they do not agree with each other, the processing proceeds to a step  1411 .  
         [0168]     On the other hand, when the port ID  702  of the record C and the port ID  501  of the record D agree with each other, the port  112  corresponding to the record D belongs to the alias corresponding to the record C. In other words, the port  112  corresponding to the record D belongs to the zone corresponding to the record A. Therefore, next, in a step  1408 , it is judged whether the WWPN consistency  505  of the record D is “1”. When the WWPN consistency  505  of the record D is “0”, the state of the zone corresponding to the record A is normal. In this case, next, the processing proceeds to the step  1411 .  
         [0169]     On the other hand, when the WWPN consistency  505  of the record D is “1”, the state of the zone corresponding to the record A is abnormal. Therefore, in a step  1409 , the value of the zone state  303  of the record A is set to “1”.  
         [0170]     It should be noted that a result of the operation in the step  1409  is reflected in the zone list-display screen  1000  displayed on the display screen  113  of the management terminal  105  through the LAN  106 . In other words, in the zone state column  1003 , the word “CONNECTION ERROR” is displayed for the zone whose value of the zone state  303  has been changed to “1”.  
         [0171]     Next, in a step  1419 , it is judged whether the e-mail address of the system administrator is registered in the memory  109 . It is possible for the system administrator to register his/her e-mail address in the memory  109  in advance. Alternatively, the system administrator may register his/her e-mail address at the time of issuing the lock request for the port  112  as shown in  FIG. 11 . When the e-mail address of the system administrator is not registered in the memory  109 , the processing proceeds to a step  1410 .  
         [0172]     On the other hand, when the e-mail address of the system administrator is registered in the memory  109 , an e-mail is transmitted to the address in a step  1420 , thereby issuing a notification showing that the state of the zone corresponding to the record A is abnormal to the system administrator.  
         [0173]     It is possible for the system administrator to know that the state of the zone corresponding to the record A is abnormal by receiving this e-mail.  
         [0174]     On the other hand, when it is judged in the step  1407  that the port ID  702  of the record C and the port ID  501  of the record D do not agree with each other or when it is judged in the step  1408  that the WWPN consistency  505  of the record D is “0”, it is judged in the step  1411  whether the record D is the last record of the port management table  204 .  
         [0175]     When the record D is not the last record of the port management table  204 , the judgment in the step  1408  is not yet made for every record of the port management table  204 . Therefore, in a step  1412 , a record next to the record D is read from the port management table  204  and is set as a new record D. Then, the processing returns to the step  1407 .  
         [0176]     On the other hand, when it is judged in the step  1411  that the record D is the last record of the port management table  204  or when it is judged in the step  1405  that the alias ID  802  of the record B and the alias ID  701  of the record C do not agree with each other, it is judged in the step  1413  whether the record C is the last record of the alias-port mapping table  206 .  
         [0177]     When the record C is not the last record of the alias-port mapping table  206 , the judgment in the step  1405  is not yet made for every record of the alias-port mapping table  206 . Therefore, in a step  1414 , a record next to the record C is read from the alias-port mapping table  206  and is set as a new record C. Then, the processing returns to the step  1405 .  
         [0178]     On the other hand, when it is judged in the step  1413  that the record C is the last record of the alias-port mapping table  206  or when it is judged in the step  1403  that the zone ID  301  of the record A and the zone ID  801  of the record B do not agree with each other, it is judged in the step  1415  whether the record B is the last record of the zone-alias mapping table  207 .  
         [0179]     When the record B is not the last record of the zone-alias mapping table  207 , the judgment in the step  1403  is not yet made for every record of the zone-alias mapping table  207 . Therefore, in a step  1416 , a record next to the record B is read from the zone-alias mapping table  207  and is set as a new record B. Then, the processing returns to the step  1403 .  
         [0180]     On the other hand, when the record B is the last record of the zone-alias mapping table  207 , the state of the zone corresponding to the record A is normal. Therefore, in a step  1417 , the value of the zone state  303  of the record A is set to “0”.  
         [0181]     Next, in the step  1410 , it is judged whether the record A is the last record of the zone management table  202 .  
         [0182]     When the record A is not the last record of the zone management table  202 , the update of every record of the zone management table  202  is not yet completed. Therefore, in a step  1418 , a record next to the record A is read from the zone management table  202  and is set as a new record A. Then, the processing returns to the step  1402 .  
         [0183]     According to this invention described above, when a zone is set through hardware zoning, it becomes possible for the system administrator to arbitrarily lock each desired port  112  belonging to the zone. When doing so, the FC-SW  103  obtains the WWPN of the device connected to the locked port  112  and stores it in the memory  109 . Following this, even when the device connected to the port  112  has been changed, unless the lock is released, the WWPN stored in the memory  109  when the port was locked is continuously stored without being changed. After that, at an arbitrary point in time, a WWPN obtained from the device connected to the port  112  and the WWPN stored in the memory  109  are compared with each other. When it is found as a result of this comparison that they do not agree with each other, it is judged that the device connected to the port  112  has been changed. Then, a notification showing that the connected device has been changed is issued to the system administrator by e-mail or through screen displaying.  
         [0184]     As a result, it becomes possible for the system administrator to know that the device connected to the locked port  112  has been changed while operating a system with ease like in the case of the conventional hardware zoning. When knowing that the connected device has been changed, it is possible for the administrator to stop the operation of the system. Alternatively, the administrator may continue the system operation. In addition, it is possible for the system administrator to restore a state before the locked port connection change.