Abstract:
There is provided an archive system that performs processing on arbitrary contents, the system including a grouping section that groups multiple archive nodes included in a cluster, a policy section that defines a requirement for performing processing on the arbitrary contents, and a control section that determines a group for performing processing on the arbitrary contents based on the group information about the definition of the grouping of the multiple archive nodes and the requirement and controls the determined group to perform the processing.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an archive system including a computer and a storage device. In particular, it relates to a technology for managing archive data in consideration of a system configuration. 
         [0003]    2. Description of the Related Art 
         [0004]    Generally, an archive system includes a host computer that performs an operation and an archive node from or to which data is read or written according to an instruction from the host computer. Here, the term “archive” refers to a part that is responsible for long-term storage of data. 
         [0005]    Here, Patent Document 1 discloses a distributed archive technology including a cluster having multiple archive nodes, wherein archive data is written to multiple archive nodes based on the data redundancy designated by the host computer so that the host computer can access the archive data even in a case where a part of the archive nodes has a failure. 
         [0006]    In the distributed archive technology, each archive node performs contents management processing on arbitrary contents (or files). Specifically, the contents management processing includes contents copy, contents deduplication, contents search and creation of an index for search. 
         [0007]    The contents copy processing is processing in which an arbitrary node copies contents stored in the archive node to another archive node. Making the contents redundant between or among archive nodes, the access to the contents is assured even when one of the arbitrary archive nodes has a failure. 
         [0008]    The contents deduplication processing is processing in which a representative arbitrary archive node consolidates and stores overlapping contents into its own arbitrary archive node, and makes a link such that other archive nodes can access to the contents stored in the arbitrary archive node, which prevents the storage of the entity of contents in other archive nodes. By consolidating contents between or among archive nodes, the amount of contents of archive data can be reduced. 
         [0009]    In the contents search processing, an arbitrary archive node creates an index such that arbitrary contents can be searched from contents stored in all archive nodes. 
         [0010]    According to the policy defined by a user or a manager, each archive node performs contents management processing. The term, “policy”, here refers to a requirement defined for performing processing including the necessity for contents management processing and/or the range of the processing. For example, when a user or a manager defines a redundancy “2” as the policy in the contents copy processing, contents stored in an arbitrary archive node is copied and stored to another archive node. In other words, same contents are stored in two archive nodes. When a user or a manager defines the policy “executable” in the contents deduplication processing, an arbitrary archive node performs the deduplication processing. Then, when a user or a manager defines the policy “executable” in the contents search processing, an arbitrary archive node searches arbitrary contents. 
         [0011]    Patent Document 1: US 2005/0120025 A1, Specification Applying the distributed archive technology under the environment in which multiple archive nodes in one archive system are scattered over two or more remote sites causes problems as follows: 
         [0012]    It is assumed that an arbitrary archive node performs the contents copy processing so that contents and copied contents can be stored in two archive nodes on a same site. If the site has a disaster or a system failure in this case, there is a possibility that a host computer may not access both of the contents and the copied contents or a possibility that both of the contents and the copied contents are lost. 
         [0013]    It is assumed that the deduplication processing on contents performed by an arbitrary archive node allows a site to have a representative archive node that stores contents and allows different remote sites to have a different archive node that have a link to the contents. In this case, in order for a host computer to access the contents held by the different archive node, the different archive node must issue an access request for the contents to the representative archive node on the different site, which may reduce the access performance. 
         [0014]    Since the processing of searching contents by an arbitrary archive node must search a wider range of contents, the searching performance may be reduced. 
         [0015]    Although archive nodes in one archive system are scattered over two or more remote sites, each archive node cannot grasp the sites and the archive nodes on the sites to perform contents management processing. 
       SUMMARY OF THE INVENTION 
       [0016]    Accordingly, it is an object of the invention to provide an archive system and a contents management method in consideration of the locations of archive nodes and contents management. 
         [0017]    According to an aspect of the invention, in order to achieve the object, there is provided an archive system that performs processing on arbitrary contents, the system including a grouping section that groups multiple archive nodes in a cluster, a policy section that defines a requirement for performing processing on the arbitrary contents, and a control section that determines a group for performing processing on the arbitrary contents based on the group information about the definition of the grouping of the multiple archive nodes and the requirement and controls the determined group to perform the processing. 
         [0018]    As a result, an archive node can be located, and predetermined processing can be performed on arbitrary contents even under an environment in which archive nodes included in one archive system are scattered over two or more remote sites. 
         [0019]    According to another aspect of the invention, there is a contents management method in an archive system that performs processing on arbitrary contents, the method including a first step of grouping multiple archive nodes in a cluster, a second step of defining a requirement for performing processing on the arbitrary contents, and a third step of determining a group for performing processing on the arbitrary contents based on the group information about the definition of the grouping of the multiple archive nodes and the requirement and controlling to perform the processing by the determined group. 
         [0020]    As a result, an archive node can be located, and predetermined processing can be performed on arbitrary contents even under an environment in which archive nodes included in one archive system are scattered over two or more remote sites. 
         [0021]    Contents management processing can be performed by recognizing the site and locating the archive nodes on the site by each archive node even under an environment in which archive nodes included in one archive system are scattered over two or more remote sites. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a block diagram showing a configuration of an archive system according to an embodiment of the invention; 
           [0023]      FIG. 2  is a block diagram showing a configuration of a host computer according to the embodiment; 
           [0024]      FIG. 3  is a block diagram showing a configuration of an archive node according to the embodiment; 
           [0025]      FIG. 4  is a block diagram showing a configuration of a storage device according to the embodiment; 
           [0026]      FIG. 5  is a block diagram showing a configuration of a management computer according to the embodiment; 
           [0027]      FIG. 6  is a diagram showing a contents management schedule table according to the embodiment; 
           [0028]      FIG. 7  is a diagram showing a mapping management table according to the embodiment; 
           [0029]      FIG. 8  is a diagram showing an index management table according to the embodiment; 
           [0030]      FIG. 9  is a diagram showing a group management table according to the embodiment; 
           [0031]      FIG. 10  is a diagram showing a policy management table according to the embodiment; 
           [0032]      FIG. 11  is a flowchart illustrating creation/update processing on the group management table according to the embodiment; 
           [0033]      FIG. 12  is a flowchart illustrating archive processing and policy setting processing according to the embodiment; 
           [0034]      FIG. 13  is a flowchart illustrating the archive processing and policy setting processing according to the embodiment; 
           [0035]      FIG. 14  is a flowchart showing contents management processing according to the embodiment; 
           [0036]      FIG. 15  is a flowchart showing copy processing according to the embodiment; 
           [0037]      FIG. 16  is a flowchart illustrating deduplication processing according to the embodiment; 
           [0038]      FIG. 17  is a flowchart illustrating index creating processing according to the embodiment; and 
           [0039]      FIG. 18  is a flowchart illustrating search processing according to the embodiment. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0040]    With reference to drawings, embodiments of the invention will be described below. It should be noted that the invention is not limited by the following descriptions. 
       [1] Archive System of Embodiment of the Invention 
       [0041]      FIG. 1  is an example showing a configuration of an archive system of an embodiment of the invention. 
         [0042]    On each of remote operation sites  700 A and  700 B in an archive system  1 , a host computer  100  connects to an archive node  200  over a LAN (or Local Area Network)  400 , and the archive node  200  connects to a storage device  300  over a SAN (or Storage Area Network)  500 . Then, the multiple remote archive nodes  200  are included in one archive cluster  201 . The archive nodes  200 , storage devices  300  and a management computer  600  are mutually connected over a management network  800 . 
         [0043]    Having described that the networks  400 ,  500  and  800  adopt different kinds of network according to this embodiment, a same kind of network may be used. Two sites will be described as examples of the operation sites, and the archive system may include three or more operation sites. 
         [0044]    Except for the case where operation sites are discriminated for description, the reference letters A and B are not given in the description below. 
         [0045]      FIG. 2  is a configuration example of the host computer  100 . The host computer  100  includes a CPU (or Central Processing Unit)  110 , a memory  120  that stores data, a hard drive  130  that stores data, an input device  140  including a keyboard, an output device  150  including a screen and a communication port  160  that performs data communication with the archive node  200 . The hardware configuration of the host computer  100  can be implemented by a generic electronic computer or an information processor (or personal computer) for example. 
         [0046]      FIG. 3  is an example showing a configuration of the archive node  200 . The archive node  200  includes a CPU  210 , a memory  220 , a hard drive  230 , an input device  240 , an output device  250 , a communication port  260  that communicates data with the host computer  100  over the LAN  400 , an IO (or Input/Output) port  270  that communicates data with the storage device  300  over the SAN  500  and a management port  280  that communicates data with other archive nodes  200 , storage devices  300  and the management computer  600  over the management network. 
         [0047]    The hard drive  230  includes a contents archive program  239 , a contents management program  231 , a copy program  232 , a deduplication program  233 , an index creating program  234 , a search program  235 , a contents management schedule table  236 , a mapping management table  237  and an index management table  238 . 
         [0048]    The contents archive program  239  determines the archive node  200  for saving contents requested to store from the host computer  100  and registers a policy (which is an argument) for performing contents management processing. The expression, “contents management processing” refers to processing to be performed for saving contents as archive data for long period of time and includes contents copy processing, contents deduplication processing and search processing including processing of creating an index required for searching contents according to this embodiment. The term, “policy”, refers to a requirement defined for performing management processing and may include a registered redundancy and/or local processing within an operation area or global processing beyond an operation area. 
         [0049]    The contents management program  231  manages such that the contents management processing can be performed normally. 
         [0050]    The copy program  232  performs contents copy processing, and the deduplication program  233  performs contents deduplication processing. 
         [0051]    The index creating program  234  creates an index required for searching contents. 
         [0052]    The search program  235  searches contents in response to a contents search request transmitted from the host computer  200  and transmits the search result to the host computer  200 . 
         [0053]    The tables  236 ,  237  and  238  will be described later. 
         [0054]    The hardware configuration of the archive node  200  can be implemented by a generic electronic computer or an information processor (or personal computer), for example. 
         [0055]      FIG. 4  is an example showing a configuration of the storage device  300 . The storage device  300  includes a controller  310  that controls the storage device  300 , a memory  320 , an IO port  350  to be used for communication with the archive node  200  of the archive cluster  201 , a management port  360  to be used for communication with the archive node  200  or management computer  600  and one or more physical disks  330 . 
         [0056]    The storage device  300  divides a storage area of the one or more physical disks  330  and manages the divided storage areas as logical volumes  340 . The storage device  300  provides multiple logical volumes  340  to the archive node  200 . The logical volume  340  includes multiple segments and assigns a storage area on the physical disk  330  to each segment so that an IO request (such as a write request and read request) from the host computer  100  to the logical volume  340  can be received and the requested contents can be exchanged. 
         [0057]      FIG. 5  is an example showing a configuration of the management computer  600 . The management computer  600  includes a CPU  610 , a memory  620 , a hard drive  630 , an input device  640 , an output device  650  and a management port  660  to be used for communication with the archive node  200  or storage device  300 . 
         [0058]    The hard drive  630  internally contains a configuration management program  633  that detects the layout of the archive nodes  200 , the layout of the storage devices  300  and mutual connection relationships upon installation of the system or addition or reduction of the archive node or nodes  200  or storage device devices  300 , a group management table  631  that manages system configuration information detected by the configuration management program  633 , a policy management table  632  that manages policy information for performing contents management processing and a policy management program  634  that exchanges policy information and updates the policy management table  632 . 
         [0059]    Notably, the hardware configuration of the management computer  600  can be implemented by a generic electronic computer or an information processor (or personal computer) for example. 
         [0060]      FIG. 6  is an example showing the contents management schedule table  236 . 
         [0061]    The contents management schedule table  236  manages the schedule for performing contents management processing. 
         [0062]    The contents management schedule table  236  includes a “Contents Management Processing” column  236 A for identifying contents management processing and a “Frequencies of Execution” column  236 B for identifying the schedule of contents management processing. 
         [0063]    For example, the contents management schedule table  236  in  FIG. 6  shows that copy processing on contents (or archive data) of the contents management processing is to be performed at 3:00 everyday. Similarly, the contents management schedule table  236  shows that the deduplication processing is to be performed at 1:00 every Tuesday and that the index creating processing is to be performed at 2:00 everyday. 
         [0064]    According to this embodiment, the archive node  200  performs processing on all connected archive data with the frequency of execution on the contents management schedule table  236 . However, processing may be performed with the frequency of execution registered for each archive data. 
         [0065]      FIG. 7  is a configuration example of the mapping management table  237 . 
         [0066]    The mapping management table  237  manages the mapping between contents and the archive node  200  that saves the contents. 
         [0067]    The mapping management processing table  237  includes a “Contents ID” column  237 A that identifies contents, which is archive data, and a “node ID” column  237 B that identifies the archive node  200  that saves the contents. 
         [0068]    For example, in a case where same contents are consolidated to the representative archive node  200  by performing the deduplication processing by the archive node  200 , a link is established between the “Node ID” column  237 B and the contents, which is an entity of a different contents ID, and a note such as “(Link to N1)” may be added. 
         [0069]    Methods for determining contents with different contents IDs as same contents may include a method that determines the identity by comparing the data of contents. Referring to the contents IDs shown in  FIG. 7 , if the contents with different IDs “/data1/a.ppt” and “data2/a.ppt” have same data, the archive node  200  determines that they are the same contents. The determination method is only an example, and the determination method is not limited to the aforesaid method. 
         [0070]      FIG. 8  is an example showing an index management table  238 . 
         [0071]    The index management table  238  manages index information for searching arbitrary contents. 
         [0072]    The index management table  238  includes a “Contents ID” column  238 A for identifying contents and an “Index Information” column  238 B for managing index information. The index information may be information for identifying arbitrary contents. The index management table  238  shown in  FIG. 8  includes attribute information such as the name of a user who creates contents and the date of the creation and index information such as a keyword in the data of contents. 
         [0073]    In the example in  FIG. 8 , the index information for searching contents with the ID “/data4/c.cad” is “Nakamura”, “Drawing” or “Tokyo”. 
         [0074]      FIG. 9  is an example showing the group management table  631 . 
         [0075]    The group management table  631  manages the correspondence relationship among an operation site  700 , an archive node  200  and a storage device  300 . The group management table  631  groups the archive nodes  200  on a same operation site  700  or the archive nodes  200  sharing one same storage device  300 . 
         [0076]    The group management table  631  includes a “Site ID” column  631 A that identifies an operation site  700 , a “Node ID” column  631 B that identifies the archive node  200  present within the operation site  700  and a “Storage Device ID” column  631 C that identifies a storage device  300  connecting to the archive node  200 . 
         [0077]    In the example in  FIG. 9 , archive nodes and storage devices are grouped for each of operation sites  700 A and  700 B. The archive nodes  200  sharing one same storage device  300  may be grouped. 
         [0078]      FIG. 10  is an example showing the policy management table  632 . 
         [0079]    The policy management table  632  manages a requirement for a case where contents management processing is to be performed on arbitrary contents. 
         [0080]    The policy management table  632  includes a “Contents ID” column  632 A that identifies contents, a “Redundancy” column  632 B indicates the redundancy of contents, a “Copy Range” column  632 C that describes the copy range of contents, a “Deduplication Range” column  632 D that describes the deduplication range of contents and a “Search Range” column  632 E that describes the valid range for searching contents. 
         [0081]    The “Redundancy” column  632 B has the required number of copies of contents. For example, a redundancy “1” means that the original contents is only required. A redundancy“2” means that two copies of contents are required. 
         [0082]    Therefore, the setting of the “copy range” depends on the number in the “Redundancy”. If the redundancy “1” is set, “the “Copy Range” column  632 C has the setting of “None” (or no copy). If the redundancy “2” or more is set, the “Copy Range” column  632 C has “Local” (which means the saving of a copy within the same site as that of the original contents) or “Global” (which means the saving of a copy to a different site from that of the original contents). 
         [0083]    The “Deduplication Range” column  632 D has the setting of “None” (no deduplication), “Local” (which means that deduplication processing within one same site is performed on overlapping contents in the range of the site) or “Global” (which means that deduplication processing not only in one site but also in other sites is performed on overlapping contents in the range of all sites where the contents exist). 
         [0084]    The “Search Range” column  632 E has the setting of “None” (which means that index information for searching contents is not created and is excluded from the search subject), “Local” (which means that index information of contents is used only within a site) or “Global” (which means that index information of contents is shared all sites). 
         [0085]    The archive system  1  according to this embodiment performs (A) detection of the layout and connection relationship of archive nodes, (B) setting of the policy and (C) contents management processing. 
       (A) Detection of the Layout and Connection Relationship of Archive Nodes 
       [0086]    The management computer  600  (or possibly a representative archive node  200 ) that centrally manages the layouts of the archive nodes  200  and the storage devices  300  detects the layout and connection relationship of archive nodes  200  upon installation of the system, upon addition or reduction of the archive nodes  200  or upon addition or reduction of the storage devices  300 . As a result of the detection, the management computer  600  groups the archive nodes  200  on a same operation site  700  or the archive nodes  200  sharing one storage device  300  and registers them to the group management table  631 . The group management table  631  is shared among the management computer  600  and the archive nodes  200 . 
       (B) Setting of Policy 
       [0087]    Upon saving of arbitrary contents to the storage device  300 , a system manager may set the policy for performing contents management processing (or processing of copy, deduplication or index creation for search) by using group information. The setting result is registered with the policy management table  632 . The policy management table  632  is shared among the management computer  600  and the archive nodes  200 . 
       (C) Contents Management Processing 
       [0088]    In order to perform contents management processing (which may be processing of copy, deduplication or index creation for search), each of the archive nodes  200  determines either within the group of the operation area  700  (that is, Local) or across multiple groups (beyond one operation area  700 ) (that is, Global) with reference to the policy management table  632 . In order to perform processing across multiple groups by each of the archive nodes  200 , the archive node  200  requests processing of copy, deduplication or index creation for search to a different archive node from the archive node with reference to the group management table  631 . 
         [0089]    The processing routines to be implemented by (A) to (C) will be described. 
         [0090]    First of all, the routine of creating or updating the group management table  631  will be described with reference to the flowchart shown in  FIG. 11 . 
         [0091]    The processing of creating or updating the group management table  631  is performed by the CPU  610  of the management computer  600  based on the configuration management program  633 . The processing is performed upon installation of the system, addition or reduction of the archive nodes  200  or addition or reduction of the storage devices. 
         [0092]    First of all, for each operation site  700 , the CPU  610  obtains the physical positional information on the archive nodes  200  and storage devices  300  and configuration information connecting the archive node  200  and the storage device  300  over the management network  800  (S 101 ). 
         [0093]    In order to initialize the group management table  631  (S 102 : YES), the CPU  610  registers site IDs, archive node IDs and storage device IDs based on the obtained physical positional information and configuration information (S 103 ) and exits the processing. 
         [0094]    In order not to initialize the group management table  631  on the other hand, the CPU  610  updates the site IDs, archive node IDs and storage device IDs based on the obtained physical positional information and configuration information (S 104 ) and exits the processing. 
         [0095]    Next, a processing routine for creating the mapping management table  237  and policy management table  634  in the implementation of archive processing for saving contents in a storage device and policy setting processing on contents will be described with reference to the flowcharts shown in  FIGS. 12 and 13 . 
         [0096]    The archive processing and policy setting processing are performed by the CPU  210  of a representative archive node  200  (which will be simply called representative CPU  210 ) based on the contents archive program  239  and are performed by the CPU  610  of the management computer  600  based on the policy management program  634 . 
         [0097]    First of all, the CPU  110  of the host computer  100  transmits a contents desired to save for a long period of time and policy information to be defined for the contents to the representative archive node  200  within an operation site  700  (S 201 ) 
         [0098]    The representative CPU  210  having received the contents and policy information performs the archive processing on the contents (S 202 ). The contents archive processing will be described later. 
         [0099]    The representative CPU  210  performs the archive processing to complete the saving of the contents and the setting of the policy information and then notifies the fact of the completion to the host computer  100  (S 203 ) and exits the processing. 
         [0100]    Next, details of contents archive processing in step S 202  in  FIG. 12  will be described. 
         [0101]    The representative CPU  210  determines the destination archive node  200  to save the contents (which will be called destination node  200 ) (S 204 ). The destination node  200  may be determined at random or may be the archive node  200  having a minimum amount of saved data or may be determined by any other methods. 
         [0102]    Next, the representative CPU  210  transmits the contents from the host computer  100  to the destination node  200  determined by step S 204  (S 205 ). 
         [0103]    The CPU  210  of the destination node  200  having received the contents transmits the received contents to the storage device  300  connecting to the own node (S 206 ). 
         [0104]    The controller  310  of the storage device  300  having received the contents saves the data of the contents to a representative logical volume  340  (S 207 ). Then, the controller  310  notifies the destination node  200  of that the data of the contents has been saved (S 208 ). 
         [0105]    The CPU  210  of the destination node  200  having received the notification updates the mapping management table  237  (S 209 ). The CPU  210  of the destination node  200  registers its own node ID and the contents ID with the mapping management table  237 . 
         [0106]    Then, the CPU  210  of the destination node  200  notifies the representative archive node  200  of that the saving of the data of the contents has completed (S 210 ). 
         [0107]    The representative CPU  210  having received the notification of the completion of the saving of the data of the contents transmits the policy information from the host computer  100  to the management computer  600  (S 211 ). 
         [0108]    The CPU  610  of the management computer  600  registers the received policy information with the policy management table  632  (S 212 ), then notifies the representative archive node  200  of the completion of the setting of the policy information (S 213 ) and exits the processing. 
         [0109]    After that, the representative archive node  200  having received the notification of the completion of the setting of the policy information from the management computer  600  notifies the host computer  100  of the completion of the saving of the contents and the completion of the setting of the policy information (S 203 ). 
         [0110]    Thus, the contents is saved in the storage device  300  connecting to the destination node  200  and is reflected to the mapping management table  237 , and the policy information on the contents is registered with the policy management table  632 . 
         [0111]    Next, the routine for contents management processing to be performed by each of the archive nodes  200  will be described with reference to the flowchart shown in  FIG. 14 . The management processing is performed by the representative CPU  210  based on the contents management program  231  and by the CPU  610  of the management computer  600  based on the policy management program  634 . 
         [0112]    First of all, the representative CPU  210  refers to the contents management schedule table  236  periodically (S 301 ) and checks whether any contents management processing that satisfies a requirement for execution exists or not (S 302 ). If some contents management processing that satisfies the requirement for execution exists (S 302 : YES), the representative CPU  210  refers to the mapping management table  237  and transmits the management computer  600  the request for the policy information on all contents, which are subjects of the management processing by the own archive node  200  (S 303 ). 
         [0113]    The CPU  610  of the management computer  600  having received the request for the policy information refers to the policy management table  632  and transmits the policy information of all contents, which are subjects of the management processing by the representative archive node  200  (S 304 ). 
         [0114]    The representative CPU  210  having received the policy information of all contents performs actual contents management processing based on the contents management schedule table  236  and the policy information (S 305 ) and exits the processing. 
         [0115]    The representative CPU  210  requests the management computer  600  the policy information on the contents, which are subjects of the management processing by the representative CPU  210 , according to this embodiment. However, the policy management table  632  may be requested. 
         [0116]    With reference to the flowcharts shown in  FIGS. 15 to 18 , a more specific routine of the contents management processing in step S 305  will be described. 
         [0117]    If the contents management processing that satisfies a requirement for execution is the copy processing on contents (S 311 : YES), the representative CPU  210  performs contents copy processing shown in  FIG. 15 . The contents copy processing is performed by the representative CPU  210  based on the copy program  232 . The case where the contents management processing is not contents copy processing (S 311 : NO) will be described later. 
         [0118]    First of all, the representative CPU  210  determines the source archive node and the destination archive node from the policy information transmitted in step S 304  (S 312 ). The representative CPU  210  refers to the mapping management table  237  and determines the archive node  200  that holds contents to be the subject of the management processing as the source archive node. The source archive node may be determined at random or may be the archive node  200  having a minimum amount of saved data or may be determined by any other methods. For example, if the copy range in the policy information on the contents to be copied is “Local” and the redundancy is “2”, the source archive node is selected from the archive nodes  200  in the same operation area. On the other hand, if the copy range in the policy information on the contents to be copied is “Global” and the redundancy is “3”, the source archive node is selected from the archive nodes  200  not only in the same operation area but also in a different operation area. For the redundancy “3”, two destination archive nodes are required. Therefore, one archive node  200  may be selected in each of the same operation area and the different operation area. Alternatively, two archive nodes  200  may be selected in a different operation area. 
         [0119]    The representative CPU  210  transmits a request for copying the contents to the determined source archive node  200  (S 313 ) 
         [0120]    The CPU  210  of the source archive node  200  (which will be simply called source CPU  210 ) having received the request for copying the contents transmits the contents to be copied to the selected destination archive node  200  (S 314 ). 
         [0121]    The CPU  210  of the destination archive node  200  (which will be simply called destination CPU  210 ) having received the request for copying the contents transmits the contents to be copied to the storage device  300  connecting to the destination archive node  200  (S 315 ). The storage device  300  having received the contents to be copied saves the data of the contents to a logical volume  340  (S 316 ) and notifies the completion of the saving of the contents to the destination archive node  200  (S 317 ). 
         [0122]    The destination CPU  210  having received the notification of the completion of the saving of the contents notifies the source archive node  200  of the contents ID, its own node ID and the completion of the saving of the contents (S 318 ). 
         [0123]    The source CPU  210  having received the notification of completion transmits the representative archive node  200  the copied contents ID, the destination node ID and the notification that the copy of the contents has completed (S 319 ). 
         [0124]    The representative archive node  200  having received the notification registers the copied contents ID and the destination node ID with the mapping management table  237  (S 320 ) and then exits the copy processing (S 305 ). 
         [0125]    Thus, the archive system  1  can create a copy of contents based on the redundancy and copy range registered with the policy management table  632 . 
         [0126]    Next, the case (S 311 : NO) where the contents management processing is not contents copy processing in step S 311  will be described. If the contents management processing that satisfies a requirement for execution is contents deduplication processing (S 331 : YES), the representative CPU  210  performs the contents deduplication processing shown in  FIG. 16 . The contents deduplication processing is performed by the representative CPU  210  based on the deduplication program  233 . The case (S 331 :NO) where the contents management processing is processing of creating an index for search will be described later. 
         [0127]    First of all, the representative CPU  210  determines the contents to be deleted based on the policy information (S 332 ). 
         [0128]    The method for determining the contents to be deleted may include comparing contents to determine whether they are identical or not, leaving arbitrary contents as representative contents from multiple contents and determining the other contents as contents to be deleted. The representative contents may be determined at random or may be contents held by the archive node  200  in the same operation area  700  as that of the representative archive node  200 . The determination method may be selected arbitrarily. The comparison range is a range defined as the deduplication range in the policy information. If the deduplication range is “Local”, overlapping contents are detected in the same operation area  700 , and the contents to be deleted are determined. If the deduplication range is “Global” on the other hand, overlapping contents are detected in not only the operation area  700  but also a different operation area  700 , and the contents to be deleted are determined. The determination method is only an example, and the determination method is not limited to the aforesaid method including a method that compares the data of contents specifically. 
         [0129]    After the contents to be deleted are determined, the representative CPU  210  refers to the mapping management table  237  and identifies the archive node  200  that holds the contents to be deleted (which will be called deletion node  200 ) and transmits a request for deleting the contents to the deletion node  200  (S 333 ). 
         [0130]    The CPU  210  of the deletion node  200  (which will be called deletion CPU  210 ) having received the request for deleting the contents transmits the request for deleting the contents to the storage device  300  connecting to the deletion node  200  (S 334 ). The deletion CPU  210  further transmits the ID of the contents to be deleted along with the deletion request. 
         [0131]    The storage device  300  having received the deletion request and the ID of the contents to be deleted deletes the data having the ID of the contents to be deleted from the logical volume  340  (S 335 ) and notifies the deletion node  200  of the completion of the deletion of the contents (S 336 ). 
         [0132]    The CPU  210  having received the notification of the completion of the deletion of the contents notifies the representative archive node  200  of the ID of the deleted contents, the own node ID and the completion of the deletion of the contents (S 337 ). 
         [0133]    The representative archive node  200  having received the notification registers the ID of the deleted contents and the ID of the deletion node with the mapping management table  237  (S 320 ). This means that the same contents are consolidated to the representative archive node  200 . Therefore, the representative archive node  200  establishes a link from the “Node ID” column  237 B corresponding to the ID of the deleted contents to the contents having the entity. 
         [0134]    The representative archive node  200  updates the mapping management table  237  and then exits the deduplication processing (S 305 ). 
         [0135]    The deletion node  200  refers to all archive nodes  200  holding the contents to be deleted. 
         [0136]    In this way, in the archive system  1 , same contents are consolidated to the representative archive node  200  based on the deduplication range registered with the policy management table  632 . 
         [0137]    Next, the case (S 331 : NO) will be described where the contents management processing is the processing of creating an index for search in step S 331 . The representative CPU  210  performs processing of creating an index as shown in  FIG. 17 . The index creating processing is performed by the representative CPU  210  based on an index creating program  234 . 
         [0138]    The representative CPU  210  extracts index information from contents held in the operation area  700  which has the representative archive node  200  (S 341 ). The index information to be extracted may be keyword information extracted from the data of contents or attribute information of a creator who creates the contents, for example. 
         [0139]    The representative CPU  210  determines whether the search range of the contents for which an index is created is global or not (S 342 ) based on the policy information transmitted from the management computer  600 . If so (S 342 : YES), the representative CPU  210  refers to the mapping management table  237  and identifies the archive node in a different operation area and holds contents having the same data (S 343 ). The archive node is identified for each contents held by the operation area  700  to which the representative archive node  200 . 
         [0140]    The representative CPU  210  transmits a request for obtaining the index information to the archive node  200 , which is identified in step S 343  and is in the different operation area  700  (which will be simply called node  200 , hereinafter) (S 344 ). 
         [0141]    The CPU  210  of the different node  200  having received the request for obtaining index information extracts the index information from the contents held by the operation area  700  which has the own node (S 345 ) and then transmits the index information to the representative archive node  200  (S 346 ). 
         [0142]    The representative CPU  210  transmits the index information extracted in step S 341  to the different node  200  holding the contents having the same data (S 347 ). 
         [0143]    The CPU  210  of the different node  200  registers the index information from the representative archive node  200  and the index information extracted in step S 345  with the index management table  238  (S 348 ) and exits the processing. 
         [0144]    In the same manner, the representative CPU  210  registers the index information from the different node  200  and the index information extracted in step S 341  with the index management table  238  (S 349 ) and exits the processing. 
         [0145]    In this way, if the search range is global, the index information created for contents having the same data can be shared with the archive node  200  in a different operation area (or group). If the search range is “Local”, the index information created for contents having same data within the range of an operation area can be shared among the archive nodes  200  present in the operation area. 
         [0146]    The search processing will be described in which the host computer  100  searches arbitrary contents after the end of the processing of creating an index for the arbitrary contents as described above. 
         [0147]    The search processing is performed by the representative CPU  210  based on the search program  235 . 
         [0148]    The host computer  100  transmits a search request to the representative archive node  200  (S 401 ). The search request contains keyword information, for example, for detecting the contents desired by the host computer  100 . 
         [0149]    The representative CPU  210  detects the contents satisfying a requirement in the received search request based on the index management table  236  (S 402 ). 
         [0150]    The representative CPU  210  transmits the detected contents to the host computer  100  and exits the processing. 
       [2] Advantages of This Embodiment 
       [0151]    As described above, according to this embodiment, each archive node can grasp a site and the location of archive nodes on the site and can perform contents management processing (including copy, deduplication, search index creation and search processing) under an environment where archive nodes included in one archive system are scattered over two or more remote sites. 
       [3] Other Embodiments 
       [0152]    Having described that the group management table  631 , policy management table  632 , configuration management program and policy management program  634  are saved in the hard drive  630  of the management computer  600 , they may be saved in the hard drive  230  of an archive node  200 . In this case, the processing to be performed by the management computer  600  as described above is performed by the representative archive node  200  or another archive node  200 .