JP6012409B2 - Image management apparatus, image management method, and program - Google Patents

Description

  The present invention relates to an image management apparatus, an image management method, and a program having a plurality of storage devices that store image files.

  In recent years, there has been provided an image management service for transmitting an image file generated by a digital camera or the like to a server and managing the image file on the server. Many image management services create thumbnails of multiple sizes in advance for index display and distribution to mobile terminals. An image management service having an image editing function creates an edited image file based on an instruction from the user. As described above, in image management services, not only original image files but also thumbnails and edited image files (hereinafter referred to as related image files) are often created and stored.

  The image management service system includes a group of content servers that store image files. The content server stores a large number of image files in the data storage device, and performs reading processing and writing processing of the image file requested by the application on the client. In such a system, access from a client to some image files frequently occurs, and the load may be concentrated on a content server storing the image files. Further, as a tendency of data access, the ratio of read requests may be much larger than the ratio of write requests. For this reason, the distribution of the load due to the read request in particular greatly affects the performance improvement of the entire system.

  As a method for reducing the load concentration on some content servers, there is a technique of creating a copy of a file that is frequently accessed in other content servers and distributing the access.

  For example, in Patent Document 1, the load status of a plurality of content servers is measured, and when an access request is received from a client, a server with a low load is selected as an access target. More specifically, when a read request is received, the server with the lowest load among the servers storing the copy of the file is selected as the read target. When a write request is received, the server with the lowest load is selected as a write target. This makes it possible to distribute access requests according to load conditions.

  In Patent Document 2, the number of times data is transferred according to a read request from a client is recorded, and a file whose number exceeds a predetermined number is copied to another content server. This enables load distribution to a plurality of content servers for files that are frequently requested to be read.

JP-A-6-332882 Japanese Patent Laid-Open No. 2002-73651

  However, the data stored in the content server is an image file, and optimal efficiency may not be realized as load distribution control when the file is read.

  In the prior art, the load is distributed by creating a copy of the file. However, if a file with a high access frequency is wide, a copy target increases and the storage area of the content server is compressed. Further, when a file with high access frequency changes from moment to moment, the creation and deletion of replicas frequently occurs, increasing the network load and processing load. Therefore, it is desirable to perform load balancing efficiently and keep duplication to a minimum.

  On the other hand, as described above, it is assumed that the content server stores not only the original image file but also the related image file. The related image file can be generated by editing the original image file or another related image file. Further, depending on the editing contents applied to the related image file, the same image file as the original image file can be generated from the related image file. That is, these image files have a replaceable relationship.

  In a content server group, even if the load on the content server storing image files where read requests are concentrated increases, the load on the content server storing the image file that can replace the image file can be low. There is sex. In other words, when the image file is read from the content server, the load is not distributed more efficiently by controlling the allocation in consideration of the possibility of substitution of the original image file and each related image file. It was.

  According to the above-described prior art, an access request is allocated to a content server that stores a duplicate file, and load distribution is not performed in consideration of an alternative file.

  The present invention has been made in view of the above problems, and when the data stored in the content server is, for example, an image file, the load can be efficiently distributed by considering the possibility of substitution between files. An object of the present invention is to provide an image management apparatus. Moreover, it aims at providing the method and program.

  An image management apparatus according to the present invention has the following configuration. That is, an image management device that mediates reading of the image file in response to a client request from a plurality of connectable storage devices that store the image file, the storage device storing the image file and the editing history When receiving a request for acquiring the image file, a management unit for managing, an acquisition unit for acquiring the load status of the plurality of storage devices, and a request for acquiring the image file, according to the load status Request allocation means for allocating the request to the plurality of storage devices, and the request allocation means refers to the editing history, and as a result, if there is an alternative file that can generate the target file, the request allocation means The request is allocated including a storage device for storage.

  According to the present invention, when an image file is read from the content server, a request is allocated in consideration of the possibility of substitution of the image file, so that the load on the content server can be efficiently distributed.

The block diagram which shows the structural example of the system of embodiment. The block diagram which shows the function structural example of a content server, a mediation server, and a client. An example of the image file stored in the content server. An example of the storage information which a storage information management part manages. A message example of a request that a client makes to a content server to acquire an image file. The flowchart which shows the flow of the process which a mediation server performs. The flowchart which shows the flow of the process which a content server performs. An example of a read task expressed in XML format. An example of the access history information which a stored information management part manages. 6 is a flowchart showing a flow of image file duplication processing. The flowchart which shows the flow of the process which a mediation server performs. The block diagram which shows the function structural example of a content server, a mediation server, and a client.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the accompanying drawings. The configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations.

<Embodiment 1>
A configuration example of a system according to the present embodiment will be described with reference to the block diagram of FIG.

  The system includes a plurality of content servers 100, 101, 102, an intermediary server 103, a client 104, and a network 122. Here, both the content servers 100 to 102 have the same configuration. Therefore, hereinafter, a configuration example of the system as the content server 100 will be described.

  The content server 100, the mediation server 103, and the client 104 can be connected via the network 122 and can communicate with each other. In FIG. 1, the number of content servers is three and the number of mediation servers and clients is one, but the number is not limited to this.

  The content server 100 provides a function for storing an image file and distributing it to the client 104. The content server 100 includes at least a CPU (Central Processing Unit) 105, a RAM (Random Access Memory) 106, a ROM (Read Only Memory) 107, a network interface 108, and an external storage device 109.

  The CPU 105 controls the operation of each unit constituting the content server 100 and performs various processes described later as what the content server 100 performs.

  The RAM 106 is a memory that temporarily stores data and control information, and serves as a work area used when the CPU 105 executes various processes.

  The ROM 107 stores fixed operation parameters and operation programs for the content server 100.

  The network interface 108 provides a function for connecting to and communicating with the network 122. The content server 100 can transmit / receive data to / from the mediation server 103 and the client 104 via the network interface 108.

  The external storage device 109 is a device that stores data, and has an interface that accepts an I / O command for reading and writing data. The external storage device 109 may be a hard disk drive (HDD), an optical disk drive, a semiconductor storage device, or other storage devices. The external storage device 109 stores computer programs and data for causing the CPU 105 to execute each process described later as what the content server 100 performs.

  The mediation server 103 provides a function for mediating a request from the client 104 to the content server 100. The mediation server 103 includes at least a CPU 110, a RAM 111, a ROM 112, a network interface 113, and an external storage device 114.

  The CPU 110 controls the operation of each unit constituting the mediation server 103 and performs various processes described later as what the mediation server 103 performs.

  The RAM 111 is a memory that temporarily stores data and control information, and serves as a work area used when the CPU 110 executes various processes.

  The ROM 112 stores fixed operation parameters, operation programs, and the like of the mediation server 103.

  The network interface 113 provides a function for connecting to and communicating with the network 122. The mediation server 103 can transmit / receive data to / from the content server 100 and the client 104 through the network interface 113.

  The external storage device 114 is a device that stores data, and has an interface that accepts an I / O command for reading and writing data. The external storage device 114 may be a hard disk drive (HDD), an optical disk drive, a semiconductor storage device, or other storage devices. The external storage device 114 stores computer programs and data for causing the CPU 110 to execute each process described later as what the mediation server 103 performs.

  In the client 104, an application for processing an image file is running, and requests the content server 100 for an image file required by the application. The client 104 includes at least a CPU 115, a RAM 116, a ROM 117, a network interface 118, and an external storage device 119. Further, depending on the form of the client 104, an input device 120 and an output device 121 are provided.

  The CPU 115 controls the operation of each unit constituting the client 104 and performs various processes described later as what the client 104 performs.

  The RAM 116 is a memory that temporarily stores data and control information, and serves as a work area used when the CPU 115 executes various processes.

  The ROM 117 stores fixed operation parameters and operation programs of the client 104.

  The network interface 118 provides a function for connecting to and communicating with the network 122. The client 104 can send and receive data to and from the content server 100 and the mediation server 103 through the network interface 118.

  The external storage device 119 is a device that stores data, and has an interface that accepts an I / O command for reading and writing data. The external storage device 119 may be a hard disk drive (HDD), an optical disk drive, a semiconductor storage device, or other storage devices. The external storage device 119 stores computer programs and data for causing the CPU 115 to execute each process described later as what the client 104 performs.

  The input device 120 is, for example, a keyboard, a mouse, or a touch panel. The output device 121 is, for example, a display.

  Next, functional configuration examples of the content server 100, the mediation server 103, and the client 104 will be described with reference to the block diagram of FIG. As described above, since the content servers 100 to 102 have the same functions, they are shown as the content server 100 in FIG.

  The content server 100 includes a request processing unit 201, a read control unit 202, and a data input / output unit 203.

  The request processing unit 201 receives a request generated by the client 104 for acquiring an image file. The request processing unit 201 includes a request receiving unit 204 for receiving a request from the client 104 and an image transmitting unit 205 for transmitting an image file corresponding to the request to the client 104.

  The read control unit 202 performs execution control of a request from the client 104 received by the request processing unit 201. The read control unit 202 includes a standby queue 206, a load measurement unit 207, and an image editing unit 208. The standby queue 206 is used to store image file reading tasks corresponding to requests received by the request processing unit 201. The load measurement unit 207 measures the load status of the content server 100 from the read task accumulated in the standby queue 206. For example, the number of tasks waiting to be read is measured as a load. Alternatively, the data size of a file to be read by a read waiting task may be measured as a load. The image editing unit 208 performs an editing process on the image file read from the data input / output unit 203 as necessary.

  The data input / output unit 203 converts the read task instructed by the read control unit 202 into an I / O command that can be interpreted by the external storage device 109 and executes it. As a result, data constituting the image file is read from the external storage device 109.

  An example of the image file stored in the content servers 100 to 102 is shown in FIG. The image file 301 is an original image, for example, an image received from a user or the like. The image file 302 is an image obtained by reducing the original image to a half size, and is used, for example, for thumbnail display. The image file 303 is an image obtained by rotating the original image by 90 degrees, and is generated by, for example, an editing instruction from the user. In the present embodiment, not only the original image file but also a plurality of related image files such as thumbnails and edited images are stored in different content servers 100 to 102.

  The image file 302 can be generated by reducing the image file 301. Therefore, when it is desired to read the image file 302 stored in the content server 101, the image file 301 stored in the content server 100 can be a substitute file. The image file 303 can be returned to the original image file 301 by rotating by -90 degrees. Therefore, when it is desired to read the image file 301 from the content server 100, the image file 303 stored in the content server 102 can be an alternative file.

  The mediation server 103 includes a request mediation unit 209 and an allocation control unit 210.

  The request mediation unit 209 includes a request reception unit 211 that receives a request from the client 104 and a request transfer unit 212 that transfers the request to the content servers 100 to 102.

  The allocation control unit 210 includes a storage information management unit 213 and a request allocation unit 214. The storage information management unit 213 manages storage information regarding the content servers 100 to 102 and the image files stored in the content servers 100 to 102. The storage information is updated when the image file is newly stored in the content servers 100 to 102 and when the image file is deleted from the content servers 100 to 102. The stored information will be described later with reference to FIG. The request allocation unit 214 determines a content server to which a request from the client 104 is allocated. Specifically, first, the content server storing the target file and alternative file specified in the request is searched based on the storage information managed by the storage information management unit 213. Next, a server with a low load is selected from among them, and a request is allocated with priority over a content server with a low load. For example, it is assumed that the content server 101 stores a request target file and the content server 100 stores a substitute file. When the load on the content server 100 is lower than that on the content server 101, the request allocation unit 214 allocates a request to the content server 100. At this time, the content server 100 needs to edit the read alternative file to generate the target file. This is performed by the image editing unit 208.

  Various applications 215 for processing image files are running on the client 104. The client 104 includes a request generation unit 216 for requesting the content servers 100 to 102 for an image file required by the application 215. The request generation unit 216 includes a request transmission unit 217 for transmitting a request to the content server, and an image reception unit 218 for receiving the requested image file.

  FIG. 4 shows an example of storage information managed by the storage information management unit 213. The storage information includes an image file ID 401, size information 402, editing history information 403, and storage server information 404. The image file ID 401 is an identifier for uniquely specifying an image file stored in the content server 100. The size information 402 represents the data size of each image file. The editing history information 403 is a history of editing processing applied to each image file, and includes an original image file ID 405, image processing content 406, and reversibility information 407 of the processing. The original image file ID 405 is an image file ID indicating the original image file before the editing process. The reversibility information 407 indicates whether or not it is possible to return to the original image by a process reverse to the process.

  Based on the editing history information 403, an alternative file that can be substituted for a certain image file can be determined. For example, an image file indicated by the image file ID 401 can be generated by applying the image processing content 406 to the image file indicated by the original image file ID 405. That is, the image file indicated by the original image file ID 405 is a substitute file for the image file indicated by the image file ID 401. Further, when the reversibility information 407 indicates reversibility, the image file indicated by the original image file ID 405 can be generated by performing a process reverse to the image processing content 406 on the image file indicated by the image file ID 401. In other words, the image file indicated by the image file ID 401 is a substitute file for the image file indicated by the original image file ID 405. As a result of referring to the editing history information 403, for example, it can be seen that there is information on the above-described alternative image file.

  The storage server information 404 is information indicating a content server in which each image file is stored. The storage server information 404 includes a server ID 408 that is an identifier for uniquely identifying each content server, and address information 409.

  FIG. 5 is a diagram illustrating a message example of a request that the client 104 makes to the content server in order to acquire an image file. A request message 501 is a message transmitted by the client 104, and a response message 504 is a message received by the client 104. The request message is composed of a syntax according to the HTTP (Hypertext Transfer Protocol) protocol. In the request message 501, the image file to be acquired is specified by the HTTP path unit 502. Further, meta information related to the request is added to the header portion 503. In the response message 504, the requested image file 507 is attached together with the meta information added to the header portion 506.

  Next, processing performed by the mediation server 103 will be described with reference to FIG. 6 showing a flowchart of the processing. The flowchart is realized by the CPU executing the control program.

  First, in step S <b> 601, the request reception unit 211 receives a request for acquiring an image file stored in the content servers 100 to 102 from the client 104.

  Next, in step S602, the request allocation unit 214 searches for a content server that stores the requested target file, and acquires the load status. The search for the content server is performed based on the storage information managed by the storage information management unit 213. The load status may be acquired from the content server every time a request is received, or may be acquired from the content server in advance at regular intervals. The load status is managed by the load measuring unit 207 of the content server.

  Subsequently, in step S603, it is determined whether there is an alternative file that can replace the requested file. The determination is made based on the editing history information 403 held by the storage information management unit 213 as described above. If no alternative file exists, the process proceeds to step S604, and if present, the process proceeds to step S605. In step S604, the server with the lowest load is selected from the content servers storing the target file.

  In step S605, the load status of the content server storing the substitute file is acquired by the same method as in step S602. In step S606, it is determined whether there is a content server that stores the substitute file that has a lower load than the content server that stores the target file. When it exists, it progresses to step S606, and when it does not exist, it progresses to step S604. In step S607, the server with the lowest load is selected from the content servers storing the substitute file.

  In step S608, the request is converted so that an alternative file is read instead of the target file. The conversion is performed, for example, by rewriting the request path portion 502 with information indicating an alternative file, and additionally adding the editing processing contents necessary for generating the target file from the alternative file in the header portion 503. An example of the request message 501 converted is shown in the request message 508. In the converted request message, the path portion 509 is rewritten from “002.jpg” of the target file to “001.jpg” of the alternative file. Further, the editing process content “Size = 1/2” necessary for generating the target file from the alternative file is added to the header portion 510.

  Finally, in step S609, the request transfer unit 212 transfers the request to the content server selected in step S604 or step S607. The transfer of the request may be performed by the mediation server 103 directly transferring the request to the content server, or by notifying the client 104 of the allocation destination and redirecting the client 104 to the content server.

  Next, processing performed by the content servers 100 to 102 will be described with reference to FIG. 7 showing a flowchart of the processing. The flowchart is realized by the CPU executing the control program.

  First, in step S701, the request receiving unit 204 receives an allocated request. Then, a read task corresponding to the request is generated and stored in the standby queue 206.

  An example in which the read task is expressed in XML format is shown in FIG. The read task includes a task ID 801, a target file 802, a generation date / time 803, and related request information 804. The task ID 801 is an identifier for uniquely identifying the read task. A target file 802 represents an image file to be read by a reading task. The generation date and time 803 represents the date and time when the reading task was generated. The related request information 804 is request information from the client 104 that requests an image file read by the reading task. The related request information 804 includes a request ID 805 and edit processing information 806. The request ID 805 is an identifier for uniquely specifying the request received in step S603. The edit processing information 806 indicates edit processing that needs to be performed on the read image file. This is a process necessary for generating a target file when an alternative file is read instead of the requested target file, and is specified in the header section 510 of the request.

  Next, in step S702, the reading task located at the head is taken out from the waiting queue 206. Then, the data input / output unit 203 accesses the external storage device 109 and executes an I / O command in order to read the image file data targeted by the read task that has been taken out.

  In step S703, the image editing unit 208 determines whether image editing is necessary for the read image file. The determination is made based on whether or not the editing process information 806 is specified for the reading task. If image editing is necessary, the target file is generated by performing editing processing in step S704.

  Finally, in step S705, the image transmission unit 205 transmits the image file read from the external storage device 109 in step S702 or the image file generated in step S704 to the client 104.

  As described above, according to the system of this embodiment, the load is low, including not only the server storing the requested file but also the server storing the substitute file from the content server group. You can choose a server as an allocation destination. Therefore, it is possible to efficiently distribute the load to the content server group.

<Embodiment 2>
In the first embodiment, the load is distributed by allocating the request among the content servers storing the substitute file as well as the request target file. In the present embodiment, an example in which a copy of an image file is further created when the load cannot be sufficiently distributed only by the method of the first embodiment will be described. The method of distributing the load by creating a copy of the file is also disclosed in the above-described prior art and the like. However, in the present embodiment, the copy is created in consideration of the possibility of substitution of the image file. Different. Since the present embodiment is basically based on the first embodiment, differences from the first embodiment will be described below. The system configuration according to this embodiment is the same as the configuration shown in FIGS.

  In the present embodiment, the image file duplication process is described as being performed after the mediation server 103 transfers the request to the allocation destination content server in step S609. However, the timing for performing the duplication processing is not limited to this, and for example, the duplication processing may be performed periodically whenever a certain period of time elapses.

  The storage information management unit 213 of this embodiment manages not only the storage information shown in FIG. 4 but also the access history information shown in FIG. The access history information includes a request ID 901, a request date and time 902, target file information 903, and accessed content server information 904.

  The image file duplication processing will be described with reference to FIG. 10 showing a flowchart of the processing. The flowchart is realized by the CPU executing the control program.

  First, in step S1001, the access history information managed by the stored information management unit 213 is referred to, and the number of accesses within a certain period of the target file is calculated. Next, in step S1002, it is determined whether the number of accesses within a certain period is greater than or equal to a predetermined value. If there is an access exceeding the predetermined value, the process proceeds to step S1003, and if not, the process ends.

  Subsequently, in step S1003, it is determined whether there is an alternative file that can replace the target file. If an alternative file exists, the process proceeds to step S1004. If no alternative file exists, the process proceeds to step S1006. In step S1004, the number of accesses within a certain period of the substitute file is calculated by the same method as in step S1001. In step S1005, it is determined whether the number of accesses within a certain period is equal to or greater than a predetermined value. If there is an access exceeding the predetermined value, the process proceeds to step S1006, and if not, the process ends.

  Finally, in step S1006, a copy of the target file is created. Duplication is performed, for example, on a server with the smallest number of accesses within a certain period of time among content servers that do not store the target file and substitute file.

  As described above, as an example of image file duplication processing, when access to the target file occurs frequently, if the alternative file does not exist or access to the alternative file occurs frequently, a method of creating a copy Indicated. Since various methods can be considered for the image file duplication processing, the method is not limited to the above-described method, and may be realized by using other methods.

<Embodiment 3>
In the present embodiment, an example will be described in which merging of requests is considered when the mediation server 103 receives and allocates a request. Request merging refers to combining multiple requests into one. Thereby, the processing load for reading the image file in the content servers 100 to 102 can be reduced. Since this embodiment is basically based on the first embodiment, the difference from the first embodiment will be described below.

  Processing performed by the mediation server 103 according to the present embodiment will be described with reference to FIG. 11 showing a flowchart of the processing. The flowchart is realized by the CPU executing the control program.

  First, in step S <b> 1101, the request reception unit 211 receives a request for acquiring an image file stored in the content servers 100 to 102 from the client 104.

  Next, in step S1102, the request allocation unit 214 searches for a content server that stores the requested file, and inquires whether there is an execution waiting request that targets the same image file. The search for the content server is performed based on the storage information managed by the storage information management unit 213. The execution waiting request is a request in a state where the reading task generated by the request is accumulated in the waiting queue 206 in the content server, and is an unprocessed request. If there is an execution waiting request, the process proceeds to step S1104. If not, the process proceeds to step S1105 (step S1103).

  In step S1104, the request is transferred to the content server having the corresponding execution waiting request.

  In step S1105, it is determined whether there is an alternative file that can replace the requested file. The determination is made based on the edit history information 403 held by the storage information management unit 213. If there is no alternative file, the process proceeds to step S1106 (ie, step S602), and if it exists, the process proceeds to step S1107.

  In step S1107, the content server storing the substitute file is searched by the same method as in step S1102, and an inquiry is made as to whether or not there is an execution waiting request for the same image file. If there is an execution waiting request, the process proceeds to step S1109, and if not, the process proceeds to step S1106 (step S1108).

  In step S1109, the request is converted so that an alternative file is read instead of the target file. The conversion is performed by the same method as in step S608. In step S1104, the request is transferred to the content server having the corresponding execution waiting request.

  In step S701, the content server that has received the request does not generate a new read task when there is a read task for reading the same image file as the target file of the new request in the standby queue 206. Instead, new request information is added to the related request information 804 of the existing read task in the waiting queue 206. As a result, a plurality of requests are merged into one reading task. For the read image file, steps S703 to 705 are repeated for the number of requests registered in the related request information 804. That is, it is possible to respond to a plurality of requests for the image file by reading the image file once.

  Thus, in this embodiment, the mediation server 103 performs allocation in consideration of request merging. As a result, the load on the content server can be reduced.

<Embodiment 4>
In the first embodiment, when an alternative file is read by the content servers 100 to 102, an image editing process for generating a target file is executed in the content server. In this embodiment, an example in which image editing processing is executed in the client 104 will be described.

  An example of functional configurations of the content server 100, the mediation server 103, and the client 104 in this embodiment is shown in FIG. The client 104 includes an image editing unit 1201 that performs image editing processing.

  A message transmitted from the image transmission unit 205 of the content server 100 to the client 104 is a response message 511. The header part 513 includes the contents of the editing process to be executed on the attached substitute file 514. By performing this editing process in the image editing unit 1201 of the client 104, an image file requested by the application 215 is generated.

  As described above, in the present embodiment, the image editing process required when the alternative file is read is performed by the client 104. Therefore, this is effective when it is not appropriate to execute the image editing process in the content server 100, such as when the CPU usage rate is high in the content server 100.

<Other embodiments>
Although the embodiment has been described in detail above, the present invention can take an embodiment as a system, apparatus, method, program, recording medium (storage medium), or the like. Specifically, the present invention may be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, an imaging device, a Web application, etc.), or may be applied to a device composed of a single device. good.

  Needless to say, the object of the present invention can be achieved as follows. That is, a recording medium (or storage medium) that records a program code (computer program) of software that implements the functions of the above-described embodiments is supplied to the system or apparatus. Needless to say, such a storage medium is a computer-readable storage medium. Then, the computer (or CPU or MPU) of the system or apparatus reads and executes the program code stored in the recording medium. In this case, the program code itself read from the recording medium realizes the functions of the above-described embodiment, and the recording medium on which the program code is recorded constitutes the present invention.

Claims (13)

An image management device that mediates reading of the image file in response to a client request from a plurality of connectable storage devices that store the image file,
A storage device storing the image file and a management means for managing an editing history;
Obtaining means for obtaining a load status of the plurality of storage devices;
A request allocating means for allocating the request to the plurality of storage devices according to the load status in order to read the requested target file upon receiving the request to acquire the image file;
With
The request allocating means allocates the request including a storage device for storing the alternative file when there is an alternative file capable of generating the target file as a result of referring to the editing history. apparatus.   2. The image according to claim 1, wherein the request allocation unit preferentially allocates the request to a storage device having a low load among a storage device that stores the target file and a storage device that stores the substitute file. Management device.   2. The image management apparatus according to claim 1, wherein the request allocating unit converts the request to a storage device that stores the substitute file when a storage device that makes the request is designated in advance. The management unit manages, as an editing history, information about whether each image file stored in the storage device can be generated by performing image editing on another image file stored in the storage device. And
The image management apparatus according to claim 1, wherein the request allocation unit determines an image file that can generate the target file by performing image editing as an alternative file of the target file.   2. The image management apparatus according to claim 1, wherein the management unit manages information indicating an original image file of an image file stored in the storage apparatus in association with the editing history.   The image management apparatus according to claim 1, wherein the management unit manages information indicating whether the image file stored in the storage apparatus can be returned to the original image file or not.   When the target file is an original image file and the image file stored in the storage device can be returned to the original image file with reference to the editing history, the stored image file is The image management apparatus according to claim 6, wherein the image management apparatus is an alternative image of the target file.   The image management apparatus according to claim 1, wherein the substitute file is an original image file of the target file. When the substitute file is read from the storage device instead of the target file, the storage device further comprises an instruction means for instructing the storage device to generate the target file by performing image editing on the substitute file. The image management apparatus according to claim 1, wherein: When the number of times the request allocating means receives the request for the image file and the alternative file serving as a substitute for the image file exceeds a predetermined value, the request allocating means The image management apparatus according to claim 1, further comprising creation means for creating a copy of the image file. The request allocating means is for reading the same image file as the target file of the request or the same image file as the alternative file in an unprocessed request that has been allocated to the storage device but not yet read. The image management apparatus according to claim 1, wherein when the unprocessed request exists, the request is allocated to a storage device to which the unprocessed request is allocated. An image management method that mediates reading of an image file in response to a client request from a plurality of connectable storage devices that store the image file,
A storage device storing the image file and a management process for managing the editing history;
An acquisition step of acquiring a load status of the storage device;
A request allocating step of allocating the request to the plurality of storage devices according to the load status in order to read the requested target file when receiving the request to acquire the image file;
With
The request allocating step allocates the request including a storage device for storing the alternative file when there is an alternative file capable of generating the target file as a result of referring to the editing history. Method.   The computer program for functioning a computer as each means of the image management apparatus of any one of Claim 1 to 11.

Images