Patent Publication Number: US-2003236790-A1

Title: Storage service method and storage service program

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a network storage service, such as a connection service, information storage service and the like that a service provider provides users through a network, and in particular, it relates to a network storage service system providing the service in accordance with the used amount of storage device of each user.  
       [0003] 2. Description of the Related Art  
       [0004] Recently, business for a storage service provider (SSP) renting storage devices (memory areas secured on a hard disk and the like) to clients and charging rental fees (storage service) has grown. Specifically, in this system, a storage service provider prepares a storage apparatus in a server (requester&#39;s processing device). A client requests the storage service provider to secure necessary storage capacity and pays a rental fee for the storage device.  
       [0005] Charging a rental fee for the use of a computer resource, including a storage apparatus is conventionally performed by not only a storage service provider but also other operators.  
       [0006]FIG. 1 is a flowchart showing the process of a conventional storage service.  
       [0007] When desiring the extension of a storage apparatus to be used through a server  2  (in the initial stage of a storage service contract), a user  3  calculates the needed capacity of the storage apparatus (step S 131 ) and notifies an SSP/manager  8  of the capacity over telephone or electronic mail (step S 132 ).  
       [0008] Then, the SSP/manager  8  receives the request from the user  3  (notice issued in step S 132 ) and allocates an area (disk area) of the storage device  9  of the requested capacity (step S 134 ). Simultaneously, the SSP/manager  8  creates a device file corresponding to the disk area in a device managing the storage device  9  (step S 135 ). Then, the SSP/manager  8  notifies the user  3  of the completion of the storage configuration (device configuration) modification (setting) (step S 136 ). It takes some time for the SSP/manager  8  to receive and respond to the request (step S 133  through S 136 ).  
       [0009] On receipt of the notice on the completion of storage structure modification (step S 137 ), the user  3  creates a device file in the server  2  (step S 138 ).  
       [0010] When the user  3  attempts to use a disk area in the storage device  9  through the server  2  by means of a write command and the like (step S 139 ), the relevant disk area in the storage device  9  can be used (step s 140 ) and the user (client)  3  is charged a fee (step S 141 ).  
       [0011] A device file is a file created in a host computer for a user/application in the host computer to access a device in a storage device and the like. In the case of Unix (R) and Windows (R), it is also called a special file and just disk information, respectively.  
       [0012] However, the conventional storage service provision and charging have the following problems.  
       [0013] Problem 1: When a storage apparatus in use rented by a storage service provider is extended in response to a client&#39;s request, the client must require the provider/manager to modify storage apparatus configuration. Therefore, the modification takes some time. Specifically, although it is called “capacity on demand”, it takes some time and labor for a client to secure his/her desired storage capacity.  
       [0014] Problem 2: In order to solve problem 1, an added storage device (extension device) must be prepared in advance. Therefore, the number of storage apparatuses to be prepared increases.  
       [0015] Problem 3: In order to solve problem 2, an added storage apparatus must be incorporated into one storage apparatus. Therefore, extensibility is restricted. For example, a plurality of storage apparatuses cannot be used in parallel.  
       [0016] Problem 4: the amount of storage device used varies and does not always increase. However, even if the used capacity decreases, the reduced capacity cannot be returned and a client must pay a fee even for the unused storage device.  
       SUMMARY OF THE INVENTION  
       [0017] The present invention is made in the situation described above, and it is an object of the present invention to provide a storage service method easily setting the a capacity that a client wants and charging a rental fee in accordance with actually used capacity, a storage service program thereof and a storage apparatus thereof.  
       [0018] The storage apparatus of the present invention is used to manage storage devices storing information. The storage apparatus comprises a storage device use detecting unit and a storage service fee calculating unit.  
       [0019] In the first aspect of the present invention, the storage device use detecting unit detects access to a storage device corresponding to a device file that is related to the storage device in advance in a requester&#39;s processing device when the requester&#39;s processing device accesses the device file.  
       [0020] Then, the storage service fee calculating unit calculates a storage service fee to be charged against the requester&#39;s processing device, based on the detection of access to the storage device.  
       [0021] In the second aspect of the present invention, the storage device use detecting unit allocates a storage device corresponding to a temporary storage device when a requester&#39;s processing device accesses a device file that is temporarily and virtually related to the storage device in advance in the requester&#39;s processing device and simultaneously detects access to the temporary storage device corresponding to the device file.  
       [0022] Then, the storage service fee calculating unit calculates a storage service fee to be charged against the requester&#39;s processing device, based on the detection of access to the temporary storage device. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0023]FIG. 1 is a flowchart showing the process of a conventional storage service;  
     [0024]FIG. 2A shows the summary of the storage apparatus of the present invention;  
     [0025]FIG. 2B is a flowchart showing the process of the storage service of the present invention;  
     [0026]FIG. 3 shows the relation between a server and a storage device;  
     [0027]FIG. 4 is a flowchart showing the process of stopping the usage of a storage device;  
     [0028]FIG. 5 shows the summary of another storage apparatus of the present invention and relation between a server and a storage device;  
     [0029]FIG. 6 is a flowchart showing the process of another storage service of the present invention;  
     [0030]FIG. 7 is a flowchart showing the process of stopping the usage of a storage device;  
     [0031]FIG. 8 shows a case where a shared pool is extended using a SAN;  
     [0032]FIG. 9 shows a case where a storage device (real device) is allocated using a routing function;  
     [0033]FIG. 10 is a flowchart showing the process of allocating a storage device using a routing function;  
     [0034]FIG. 11 shows the configuration of the storage apparatus of the present invention; and  
     [0035]FIG. 12 shows the loading onto a computer of the storage service program of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
     [0036] The present invention adopts the following configuration in order to solve the problems.  
     [0037] Specifically, according to the one aspect of the present invention, the storage service method, storage service program and storage apparatus of the present invention are realized in a storage apparatus managing storage devices that a requester&#39;s processing device accesses to store information. First, when the requester&#39;s processing device accesses a device file that is related to the storage device in advance in the requester&#39;s processing device, access to a storage device corresponding to the device file is detected. Then, a storage service fee to be charged against the requester&#39;s processing device is calculated based on the detection of access to the storage device.  
     [0038] In the storage service method, storage service program and storage apparatus of the present invention, it is preferable for access to the storage device to be detected by means of a write command to instruct writing into the storage device.  
     [0039] In the storage service method, storage service program and storage apparatus of the present invention, it is preferable for access to the storage device to be detected by means of a special use declaration command to declare the use of a storage device.  
     [0040] In the storage service method, storage service program and storage apparatus of the present invention, it is preferable for a storage device of an arbitrary size to be set when a storage device and a device file are related to each other.  
     [0041] According to another aspect of the present invention, the storage service method, storage service program and storage apparatus of the present invention realized in a storage apparatus managing storage devices that a requester&#39;s processing device accesses to store information. First, when the requester&#39;s processing device accesses a device file that is related to the storage device in advance in the requester&#39;s processing device, a storage device corresponding to the temporary storage device is allocated and simultaneously, access to a temporary storage device corresponding to the device file is detected. Then, a storage service fee to be charged to the requester&#39;s processing device is calculated based on the detection of the access to the storage device.  
     [0042] In the storage service method, storage service program and storage apparatus of the present invention, it is preferable for access to a storage device to be detected by means of a write command to instruct writing onto a storage device and it is preferable for a storage device corresponding to the temporary storage device to be allocated by means of the write command.  
     [0043] In the storage service method, storage service program and storage apparatus of the present invention, it is preferable for access to the storage device to be detected by means of a special use declaration command to declare the use of a storage device.  
     [0044] In the storage service method, storage service program and storage apparatus of the present invention, it is preferable for arbitrary storage device to be secured when a storage device corresponding to the temporary storage device is attempted to be allocated.  
     [0045] In the storage service method, storage service program and storage apparatus of the present invention, it is preferable for a temporary storage device and a storage device to be allocated through a storage area network (SAN).  
     [0046] In the storage service method, storage service program and storage apparatus of the present invention, it is preferable for a temporary storage device and a storage device to be allocated based on a transmission route established by routing.  
     [0047] The preferred embodiments of the present invention are described below with reference to the drawings.  
     [0048]FIG. 2A shows the summary of the storage apparatus of the present invention.  
     [0049] In FIG. 2A, it is preferable for servers (servers A, B and C)  2 , which are requesters&#39; processing devices, to be connected to a terminal device that a client uses, which is not shown in FIG. 2A. It is preferable for the servers  2  to access a storage apparatus  1  through a network, such as the Internet and the like.  
     [0050] The servers  2  can also be connected to the storage apparatus  1  by a personal computer and the like through the Internet.  
     [0051] The storage apparatus  1  manages storage devices  12  storing information. The storage apparatus  1  comprises a use detecting mechanism  11  and a storage service fee calculating unit, which is not shown in FIG. 2A. The server  2  comprises device files  21  created in accordance with the storage devices  12 .  
     [0052] The use detecting mechanism  11  detects access to a storage device  12  corresponding to a device file  21  when the server  2  accesses a device file  21  that is related to the storage device  12  in advance.  
     [0053] Then, the storage service fee calculating unit calculates a storage service fee to be charged against the server  2 , based on the detection of the access to the storage device  12  in the server  2 .  
     [0054] Thus, device files  21 , which in a general OS, are special files for processing (reading/writing) external devices in the same way as ordinary files are created in advance so that an area in the storage devices  12  can be used by executing a read/write command in an external device. Thus, the storage apparatus  1  becomes visible from the server  2  through the device file  21  of the server  2 . The server  2  can access a storage device  12  by using this device file  21  in the server  2 .  
     [0055] By adopting such a configuration, the server  2  can timely use the necessary memory capacity (disk capacity) and charge a fee only for the actual used amount of the storage device  12 .  
     [0056]FIG. 2B is a flowchart showing the process of the storage service of the present invention.  
     [0057] First, in step S 21 , the user  3  requests the server  2  to secure the capacity of a device (storage device  12 ) that the user  3  wants to set or to extend, using a terminal or directly. At this time, an operation to be performed at the time of capacity shortage can also be specified.  
     [0058] In step S 22 , the server  2  receives the instruction (request) from the user  3  and issues a command to secure a storage device  12  with the requested capacity, to the storage apparatus  1 .  
     [0059] In step S 23 , the storage apparatus  1  receives the command to secure the capacity requested by the server  2 , and in step S 24 , it judges whether the requested capacity is less than the remaining capacity of the storage device  12  (less than the remaining capacity of a hard disk that the storage apparatus  1  can use).  
     [0060] If in step S 24  it is judged that the requested capacity is more than the remaining capacity (no in step S 24 ), in step S 25  it is judged whether the operation to be performed at the time of capacity shortage specified by the user  3  is “to immediately judge it to be error” or “to secure as much capacity as possible”.  
     [0061] If in step S 25  it is judged that the operation is “to immediately judge it to be an error”, the storage apparatus I issues an error notice to the server  2 . Then, on receipt of this error notice (step S 26 ), the server  2  displays the error notice on the monitor of the user  3  (terminal of the user  3 ) or e-mails the error notice to the user  3 .  
     [0062] If in step S 25  it is judged that the operation is “to secure as much capacity as possible”, in step S 27  the storage apparatus  1  secures a storage device  12  with the maximum available capacity in a disk and formats the disk.  
     [0063] If in step S 24  it is judged that the requested capacity is less than the remaining capacity (yes in step S 24 ), in step S 28  the storage apparatus  1  secures a storage device  12  with the requested capacity in a disk and formats the disk.  
     [0064] After in step S 27  or S 28  the disk is formatted, in step S 29  the formatted disk area (Logical Unit Number (LUN)) can be set to be used only by a designated server  2 . An LUN is linked (related) to a device file  21  and the device file  21  is allocated to each server used by the user  3 . Therefore, only a target user  3  (with a user ID) is allowed to access the disk.  
     [0065] After the setting in step S 29  finishes, a completion notice is issued to the server  2 . On receipt of this completion notice (step S 30 ), the server  2  displays the completion notice on the monitor of the user  3  (terminal of the user  3 ) or e-mails the completion notice to the user  3 .  
     [0066] If the processes up to step S 30  are performed, the capacity of a storage device  12  can be secured. Specifically, if the server  2  that has received the request from the user  3  designates the capacity of the storage device  12  in the storage apparatus  1  by means of a command before the use of the storage device  12  is declared, the storage apparatus  1  can dynamically prepare the capacity of a target storage device  12  based on the instruction and can secure the capacity for the user  3 .  
     [0067] In step S 31 , the user  3  creates a new file, and transfers it or copies it using his/her device file  21  owned by the server  2 . Specifically, in step S 32 , the server  2  receives a request for a write command and issues a write command (step S 33 ).  
     [0068] Then, in step S 34 , the storage apparatus  1  receives the write command.  
     [0069] On receipt of the write command in step S 34 , the storage apparatus  1  transfers the write command to the use detecting mechanism  11  of the storage apparatus  1 , and in step S 35 , the detecting mechanism  11  detects the write command. Then, in step S 36 , client information is obtained by combining the server ID of the issuer of the write command with the disk area (LUN) of a storage device  12  to be written onto (access permission table  13 A described later), and in step S 37 , a fee to be charged against the user  3  of the server  2  that has issued the write command, is calculated.  
     [0070] Thus, a write command is used as a signal for the server  2  to actually use a storage device  12 , and this write command is detected by the use detecting mechanism  11 . By providing the storage apparatus  1  with the use detecting mechanism  11 , the storage apparatus  1  can detect the use of the storage device  12  by the server  2  and a fee can be charged against the user  3  of the server  2 .  
     [0071] Alternatively, instead of the write command, a special use declaration command to declare the use of a storage device  12  can be issued to a storage device  12  to be used, by the server  2 , and the storage device  12  can also be allocated when this use declaration is issued.  
     [0072]FIG. 3 shows the relation between a server and a storage device.  
     [0073] As described above, the server  2  and device  12  are related. This relation is realized by, for example, the access permission table  13 A shown in FIG. 3.  
     [0074]FIG. 4 is a flowchart showing the process of stopping the use of a storage device.  
     [0075] First, in step S 41 , the user  3  requests the server  2  to secure the capacity and area of a device (storage device  12 ) that he/she wants to stop, using a terminal or directly.  
     [0076] In step S 42 , the server  2  receives the instruction (stop use request) from the user  3  and issues a command (use setting stop command) to stop using a designated storage device  12 .  
     [0077] In step S 43 , the storage apparatus  1  receives the use setting stoppage command issued by the server  2  in step S 42 . Then, in step S 44 , the device  1  rewrites the relevant place in the access permission table  13 A and simultaneously, it releases the requested storage device and area of the device that have been allocated by the server  2  (the relation between the server  2  and storage device  12  is released).  
     [0078] Then, in step S 45 , the device  1  reduces the fee in proportion to the reduced capacity and issues a completion notice to the server  2 .  
     [0079] On receipt of this completion notice (step s 46 ), the server  2  displays the completion notice on the monitor of the user  3  (terminal of the user  3 ) or e-mails the completion notice to the user  3 .  
     [0080]FIG. 5 shows the summary of another storage apparatus of the present invention and the relation between a server and a storage device.  
     [0081] In FIG. 5, it is preferable for servers (servers A, B and C)  2  to be connected to the terminal device of a client, which is not shown in FIG. 5, and the servers  2  can access the storage apparatus  1  through a network, such as the Internet and the like.  
     [0082] The storage apparatus  1  manages the storage devices  12  storing information. The device  1  comprises a use detecting mechanism  11  and a storage service fee calculating unit, which is not shown in FIG. 5. Each of the servers  2  comprises device files  21  each of which is virtually related to a temporary storage device  14  corresponding to a storage device  12  in advance.  
     [0083] The temporary storage device  14  is a table where storage devices  12  are related  1  to  1  to device files  21 .  
     [0084] If the server  2  accesses a device file  21  that is virtually related to a temporary storage device  14  corresponding to a storage device  12 , the use detecting mechanism  11  allocates a storage device  12  corresponding to the temporary storage device  14 , and simultaneously it detects access to the temporary storage device corresponding to the device file  21 .  
     [0085] Then, the storage service fee calculating unit calculates a storage service fee to be charged against the server  2 , based on the detection of the access to the temporary storage device  14 .  
     [0086] By creating in advance a device file  21  that is related to a temporary storage device  14  in the server  2 , the storage apparatus  1  becomes visible from the server  2  through the device file  21  of the server  2 . Therefore, by using a device file  21  in the server  2 , the server  2  can access a storage device  12  through a temporary storage device  14 .  
     [0087] According to such a configuration, the server  2  can timely use the necessary memory capacity (disk capacity) and can charge a rental fee in accordance with the actually used amount of the storage device  12 .  
     [0088] The relation between the server  2  and temporary storage device  14 /storage device  12  can be realized by, for example, the access permission table  13 B shown in FIG. 5.  
     [0089] An aggregate of storage devices  12  is called a “shared pool”.  
     [0090]FIG. 6 is a flowchart showing the process of another storage service of the present invention.  
     [0091] First, in step S 61 , the user  3  requests the server  2  to secure the capacity of a device (storage device  12 ) that he/she wants to set or extend, using a terminal or directly. At this time, an operation to be performed at the time of capacity shortage can also be specified.  
     [0092] In step S 62 , the server  2  receives the instruction (request) from the user  3  and issues a command to set up a storage device  12  with the requested capacity to the storage apparatus  1 .  
     [0093] In step S 63 , the storage apparatus  1  receives the command to secure the capacity that the server  2  has issued in step S 62 , and in step S 64  it judges whether the requested capacity can be secured by an aggregate of storage devices  12  (shared pool) corresponding to a temporary storage device  14 .  
     [0094] If in step S 64  it is judged that the requested capacity cannot be secured (no in step S 64 ), in step S 65  it is judged whether the operation to be performed at the time of capacity shortage (when there is no corresponding storage device  12 ) specified by the user  3  is “to immediately judge it to be error” or “to secure as much capacity as possible”.  
     [0095] If in step S 65  it is judged that the instruction is “to immediately judge it to be error”, the storage apparatus  1  issues an error notice to the server  2 , and the server  2  displays the error notice on the monitor of the user  3  (terminal of the user  3 ) or e-mails the error notice to the user  3 .  
     [0096] If in step S 65  it is judged that the instruction is “to secure as much capacity as possible”, in step S 67  the storage apparatus  1  secures a storage device  12  with the maximum capacity in the unused area of the shared pool (storage devices  12 ) of a disk and formats the disk.  
     [0097] If in step S 64  it is judged that the requested capacity can be secured (yes in step S 64 ), in step  568  the storage apparatus  1  secures a storage device  12  with the requested device capacity in the unused area of the shared pool of a disk and formats the disk.  
     [0098] After in steps S 67  or S 68  the disk is formatted, in step S 69  the formatted disk area (Logical Unit Number (LUN)) can be set to be used only by a designated server  2 . A LUN is linked (related) to a device file  21 , and the device file  21  is allocated to each server  2  used by the user  3 . Therefore, only a user  3  (with the user ID) is allowed to access the disk.  
     [0099] After the setting in step S 69  finishes, a completion notice is issued to the server  2 . On receipt of the completion notice (step S 70 ), the server  2  displays the completion notice on the monitor of the user  3  (terminal of the user  3 ) or e-mails the completion notice to the user  3 .  
     [0100] If the processes up to step S 69  are performed, the capacity of a storage device  12  can be secured. Specifically, if the server  2  that has received the request from the user  3  requests the storage apparatus  1  to secure the capacity of the storage device  12  by means of a command before the use of the storage device  12  is declared, the storage apparatus  1  can dynamically prepare the capacity of a target storage device  12  based on the instruction and can secure the capacity for the user  3 .  
     [0101] In step S 71 , the user  3  creates a new file, and transfers it or copies it using his/her device file  21  owned by the server  2 . Specifically, in step S 72 , the server  2  receives a request for a write command and issues a write command to the storage apparatus  1  (step S 73 ).  
     [0102] Then, in step S 74 , the storage apparatus  1  receives the write command.  
     [0103] On receipt of the write command in step S 74 , the storage apparatus  1  transfers the write command to the use detecting mechanism  11  of the storage apparatus  1  and in step S 75 , the use detecting mechanism  11  detects the write command. Then, in step S 76 , client information is obtained by combining the server ID of the issuer of the write command with the disk area (LUN) of a storage device  12  to be written onto (access permission table  13 B described later), and in step S 77 , an area in the unused area of the shared pool is allocated to the designated user  3 . Then, in step S 78 , a fee to be charged against the user  3  of the server  2  that has issued the write command is calculated.  
     [0104] Thus, a write command is used as a signal for the server  2  to actually use the storage device  12 , and this write command is detected by the use detecting mechanism  11 . By providing the storage apparatus  1  with the use detecting mechanism  11 , the storage apparatus  1  can detect the use of the storage device  12  by the server  2 , and a fee can be charged against the target user  3  of the server  2 .  
     [0105] Alternatively, instead of the write command, a special use declaration command to declare the use of the storage device  12  can be issued to a storage device  12  to be used by the server  2 , and the storage device  12  can also be allocated when this use declaration is issued.  
     [0106] As described above, in another storage service of the present invention, a device file  21  that is related to a storage device (real device), is created in advance in the server, as with the storage service of the present invention described with reference to FIG. 2B. However, in this case, a virtual temporary storage device (device)  14  is used for a storage device. A fixed area of the storage device  12  is used for a temporary storage device  14  for each server and each area for future extension of the temporary storage device  14  is linked to the shared pool (common area unit) of the storage device  12 . However, the fixed area of the storage device  12  is not actually allocated until there is an additional instruction from the user  3 . Specifically, the total capacity of the area for extension of all the servers  2  is larger than the capacity of the shared pool.  
     [0107]FIG. 7 is a flowchart showing another process of stopping the use of a storage device.  
     [0108] First, in step S 79 , the user  3  requests the server  2  to secure the capacity and area of a device (storage device  12 ) that the user  3  wants to stop, using a terminal or directly.  
     [0109] In step S 80 , the server  2  receives the instruction (use stoppage request) from the user  3  and issues a command (use setting stoppage command) to stop using the designated storage device  12 , to the storage apparatus  1 .  
     [0110] In step S 81 , the storage apparatus  1  receives the use setting stoppage command issued by the in the access permission table  13 B. Simultaneously, the device  1  releases the requested storage device of the device area that has been allocated by the server  2  and returns the storage device to the shared pool (releases the relation between the server  2  and temporary storage device  14 /storage device  12 ).  
     [0111] Then, in step S 835 , the device  1  reduces the rental fee in proportion to the reduced capacity and issues a completion notice to the server  2 .  
     [0112] On receipt of this completion notice (step S 83 ), the server  2  displays the completion notice on the monitor of the user  3  (terminal of the user  3 ) or e-mails the completion notice to the user  3 .  
     [0113]FIG. 8 shows a case where the shared pool is extended using a SAN.  
     [0114] Although the shared pool described above is included in the storage apparatus  1 , the servers  2  (servers A and B), a virtual storage managing apparatus  6  with the use detecting mechanism  11  and temporary storage devices  14  and a real storage apparatus  5  (real storage apparatuses A and B) with storage devices  12  being real devices can also be connected to one another through a SAN (Storage Area Network) with a switch  41 .  
     [0115] By providing the use detecting mechanism  11  described above for the virtual storage managing apparatus  6 , an arbitrary unused storage device  12  of the storage devices  12  (real devices) in the real storage apparatus  5  managed by the virtual storage managing apparatus  6  can be allocated as a real device of the designated server  2  when the use detecting mechanism  11  detects the use of a storage device  12 .  
     [0116]FIG. 9 shows an example of allocating a storage device (real device) using a routing function.  
     [0117] In the example shown in FIG. 9, a storage device  12  is allocated by controlling a switch device  41  (device with a switching function) that realizes a transmission line between the server  2  and real storage apparatus  5  in a SAN  4  by a routing function.  
     [0118] First, a temporary storage device (device)  14  is created in the real storage apparatus  5 , and a real storage device  12  can be managed through a temporary storage device  14  before the real storage device is actually used.  
     [0119] Then, an access path managing mechanism  71  is newly provided for a special server  7 . If a storage device  12  (real device) is needed, the server  2  requests the access path managing mechanism  71  to secure a necessary capacity/type. Then, the access path managing mechanism  71  establishes a new real access path by selecting a real storage device  12  in response to the request and modifying the routing of the switch device  41 .  
     [0120]FIG. 10 is a flowchart showing the process of allocating a storage device using the routing function.  
     [0121] First, the initial settings of the access path managing mechanism  71  and switch device  41  shown in step S 101  and S 102 , respectively, are performed. However, these initial settings are not indispensable. Specifically, in step S 101 , the access path managing mechanism  71  requests a route setting such that each server  2  can access a temporary storage device  14  (temporary device), and in step S 102  the switch device establishes routes from each server to the temporary storage device  14 .  
     [0122] In step S 103 , the server  2  selects a necessary device capacity (capacity of storage device  12 ) and the type of a storage device  12  (for example, manufacturer) and issues a command to request them.  
     [0123] Then, in step S 104 , the access path managing mechanism  71  receives the command issued in step S 103 , and in step S 105 , it selects the requesting server  2  and a target storage device  12 , and issues a routing (route) setting command to the switch device  41 .  
     [0124] Then, in step S 106 , the switch device  41  receives the routing setting command, and in step S 107 , it sets a routing (route) and establishes anew access path (step S 108 ).  
     [0125] Then, in step S 109 , the access path managing mechanism  71  issues a normal termination reply, and in step S 110 , it starts charging the fee against the client (user  3 ), based on a received user ID.  
     [0126] Then, in step S 111 , the server  2  receives the normal termination reply, and in step S 112 , the storage device  12  becomes ready to be used.  
     [0127] Although the preferred embodiments of the present invention are described so far with reference to the drawings, the storage apparatus of the present invention is not limited to those preferred embodiments as long as the function is realized. The storage apparatus can be a single device, a system composed of a plurality if devices or an integrated device, or a system performing the process through a network, such as a LAN, WAN and the like.  
     [0128] As shown in FIG. 11, the storage apparatus can also be realized by a system comprising a CPU  1101 , a memory  1102 , such as a ROM and a RAM, an input device  1103 , an output device  1104 , an external storage device  1105 , a medium driving device  1106 , a portable storage medium  1110 , which are all connected to one another by a bus  1109 . Specifically, the storage apparatus can be realized if the storage apparatus  1105  is provided with a software program code for realizing the preferred embodiment of the system described above that is recorded on the memory  1102 , such as a ROM and a RAM, external storage device  1105  or portable storage medium  1110 , and the computer of the storage apparatus reads the program code.  
     [0129] In this case, the program code read from the portable storage medium  1110  or the like realizes the new function of the present invention, and the portable storage medium  1110  or the like on which is recorded the program code, constitutes the present invention.  
     [0130] For the portable storage medium  1110  providing the program code, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a DVD-ROM, a DVD-RAM, a magnetic tape, a non-volatile memory card, a ROM card, a variety of storage media storing data through a network connecting device  110  (in other words, a communication line), such as electronic mail or personal computer network or the like can be used.  
     [0131] As shown in FIG. 12, if a computer  1200  executes program code read into memory  1201 , the function of the preferred embodiment described above can be realized. Alternatively, if an OS operating on the computer  1200  performs a part of the actual process or the entire process according to the instructions of the program code, the function of the preferred embodiment described above can be realized.  
     [0132] Furthermore, if program code read from a portable storage medium  1210  or a program (data) provided by a program (data) provider is written into the memory  1201  provided for a function extension board inserted in the computer  1200  or a function extension unit connected to the computer  1200 , and a CPU provided for the function extension board or unit performs a part of the actual process or the entire process according to the instructions of the program code, the function of the preferred embodiment described above can also be realized.  
     [0133] In other words, the present invention is not limited to the preferred embodiments described above, and it can take a variety of configurations and forms as long as it doesn&#39;t deviate from the subject matter of the present invention.  
     [0134] As described above, according to the present invention, a storage device can be immediately used as requested.  
     [0135] Furthermore, according to the present invention, when a client wants to extend storage device that a storage service provider rents, the desired storage capacity can be secured with no added time or labor.  
     [0136] Furthermore, according to the present invention, there is no need to prepare storage device to be added in advance by increasing the number of storage devices to be prepared.  
     [0137] Furthermore, according to the present invention, storage device can be provided across a plurality of storage apparatuses, resulting greater extensibility.  
     [0138] Furthermore, according to the present invention, when the storage capacity in use decreases, the extra capacity can be retuned and there is no need to pay a rental fee for storage device that was not used.  
     [0139] Furthermore, according to the present invention, storage capacity can be easily set as a client wants, and a rental fee can also be charged in accordance with the actually used storage capacity.