JP5909760B2 - Placement destination determination system, placement destination determination method, and computer program - Google Patents

Description

  The present invention relates to a technique for determining in which data center each data is arranged in a system including a plurality of data centers.

Conventionally, it has been proposed to realize a virtual DC by linking various resources of a plurality of data centers (DC) (for example, see Patent Document 1). In the virtual DC, a wide-area resource pool that releases various resource restrictions on service requests is realized. Further, the virtual DC realizes high availability capable of maintaining service continuity even when a failure occurs in the DC base.
In the distributed DC, a storage for arranging files is also operated. However, since there is a difference in the resource performance of each site, the time required for access differs depending on the arrangement destination even for the same file. Therefore, in order to improve the service quality, it is necessary to place the file at an appropriate base. It has been proposed to realize such an arrangement using, for example, ILM (Information Lifecycle Management).

JP 2007-310715 A

However, when a file to be used is located at a physically distant base, there is a problem that access quality is deteriorated due to a network delay from the user terminal to the data center where the file is located.
In view of the above circumstances, an object of the present invention is to provide a technique for suppressing a decrease in access quality caused by network delay.

  According to one aspect of the present invention, an evaluation unit that evaluates, for each data center, a delay evaluation value related to a delay that occurs in access to the data when the data is arranged, based on the delay evaluation value. And a determination unit that determines a data center to which each data is to be allocated.

  One aspect of the present invention is the above-described placement destination determination system, wherein a point-to-point delay evaluation value relating to a delay occurring between a user terminal located at a certain point and each data center is obtained for each combination of the data center and the point. A point-to-point delay evaluation value acquisition unit to acquire, and a history information acquisition unit to acquire history information of access to each data from the user terminal, the evaluation unit, the point-to-point delay evaluation value and the history The delay evaluation value is evaluated based on the information.

  According to one aspect of the present invention, an evaluation step of evaluating, for each data center, a delay evaluation value related to a delay that occurs in access to the data when the data is arranged, based on the delay evaluation value. And a determination step of determining a data center that is an allocation destination of each data.

  According to one aspect of the present invention, an evaluation step of evaluating, for each data center, a delay evaluation value related to a delay that occurs in access to the data when the data is arranged, based on the delay evaluation value. A computer program for causing a computer to execute a determination step of determining a data center as a placement destination of each data.

  According to the present invention, it is possible to suppress a decrease in access quality caused by the physical distance.

It is a system configuration | structure figure showing the system configuration example of a data distribution system. It is a schematic block diagram which shows the specific example of a function structure of a data center. It is a figure which shows the specific example of an access history table. It is a figure which shows the specific example of a delay evaluation value table between points. It is a schematic block diagram which shows the specific example of a function structure of an arrangement | positioning destination determination apparatus. It is a figure which shows the specific example of the delay evaluation value table between points memorize | stored in the delay evaluation value memory | storage part between points. It is a figure which shows the specific example of the evaluation content of a delay evaluation value. It is a figure showing the specific example of the magnitude | size of the bad influence to the data distribution system which arises by delay. It is a schematic block diagram showing the specific example of the function structure of the modification of an arrangement destination determination apparatus. It is a figure showing the specific example of the timing information table which a timing information storage part memorize | stores. It is a flowchart showing the flow of a process of the determination part in a modification. It is a figure which shows the specific example of an arrangement | positioning destination table. It is a flowchart which shows the specific example of a process of a determination part. It is a figure showing the specific example of the flow of a process when a user terminal accesses a file.

[Overview]
First, an outline of a data distribution system according to an embodiment of the present invention will be described. The data distribution system includes a plurality of data centers. The data distribution system also includes an arrangement destination determination system. Each data center is installed at a different point. The placement destination determination system evaluates an evaluation value (delay evaluation value) related to a delay that occurs in access from the user terminal to each data center. The placement destination determination system determines the data center that is the placement destination of each file so that the delay evaluation value becomes low. For example, the placement destination determination system acquires an evaluation value (inter-point delay evaluation value) regarding a delay that occurs between the user terminal and the data center, and history information on access to each file from the user terminal. The placement destination determination system may evaluate, for each data center, a delay evaluation value related to a delay that occurs in accessing a file when the file is placed for the file whose placement destination is determined. The data distribution system moves each file to the determined placement destination according to the placement destination determined by the placement destination determination system.

[Details]
Next, details of the data distribution system according to an embodiment of the present invention will be described. FIG. 1 is a system configuration diagram illustrating a system configuration example of a data distribution system. The data distribution system shown in FIG. 1 includes seven data centers 10 (10-A to 10-G) and an arrangement destination determination device 50.

Each data center 10 is arranged at a different point. Therefore, the delay that occurs when accessing each data center 10 from a certain user terminal differs for each data center 10 even when the same file is accessed. Such a difference in delay occurs depending on a physical distance between the user terminal and the data center 10, a network facility between the user terminal and the data center 10, and the like.
The placement destination determination device 50 functions as the placement destination determination system of the present invention, and determines the data center that is the placement destination of each file.

FIG. 2 is a schematic block diagram illustrating a specific example of a functional configuration of the data center 10. The data center 10 includes a file arrangement optimization device 20, an inter-DC connection device 205, a redirect device 401, a gateway (GW) 402, and one or more storage devices 30. In the example of FIG. 2, the data center 10 includes n storage devices 30 (30-1 to 30-n) (n is an integer of 1 or more).
The file arrangement optimizing device 20 includes a CPU (Central Processing Unit) connected via a bus, a memory, an auxiliary storage device, and the like, and by executing a gateway program, an access history management unit 201, an access history storage unit 202, a point It functions as an apparatus including the inter-point delay evaluation value management unit 203 and the inter-point delay evaluation value storage unit 204. Note that all or part of each function of the file layout optimization device 20 is realized using hardware such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA). Also good.

The access history management unit 201 records information on access history (access history information) in the access history storage unit 202 every time a user terminal accesses the data center 10 provided with the access history management unit 201. Further, the access history management unit 201 notifies the access history information recorded in the access history storage unit 202 at a predetermined timing.
The access history storage unit 202 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The access history storage unit 202 stores an access history table as a specific example of access history information.

  FIG. 3 is a diagram showing a specific example of the access history table. The access history table is a table in which access point information is associated with each file ID. The file ID is identification information of a file arranged in the data center 10 provided with itself (access history storage unit 202). The fact that the file is arranged in the data center 10 indicates that the file is recorded in the storage device 30 of the data center 10. The access point information is information indicating the position of the user terminal that has accessed the file indicated by the file ID. For example, the access history table shown in FIG. 3 includes a user terminal located at point A, a user terminal located at point D, and a user terminal located at point C for the file whose file ID is “0001”. It means that there was access from.

The inter-point delay evaluation value management unit 203 acquires, for each data center 10, an evaluation value (inter-point delay evaluation value) related to a delay that occurs in access from a user terminal at a point where the data center 10 provided with the inter-point delay is located. The point-to-point delay evaluation value management unit 203 records the acquired point-to-point delay evaluation value in the point-to-point delay evaluation value storage unit 204.
The point-to-point delay evaluation value storage unit 204 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The point-to-point delay evaluation value storage unit 204 stores a point-to-point delay evaluation value table. FIG. 4 is a diagram illustrating a specific example of the inter-point delay evaluation value table. The inter-point delay evaluation value table shown in FIG. 4 shows a specific example of the inter-point delay evaluation value table of the data center 10 located at the A point. The inter-point delay evaluation value table is obtained from the user terminal located at a certain point (A point in the case of FIG. 4) with the data center 10 installed at each point (A, B, C, D,...). This represents the point-to-point delay evaluation value regarding the delay occurring between. In the case of FIG. 4, the point-to-point delay evaluation values generated between the user terminal located at the point A and the data center 10 installed at the points A, B, C, and D are “1”, “2”, “3” and “4”.

  Next, a specific example of the process for acquiring the inter-point delay evaluation value table will be described. First, the inter-point delay evaluation value management unit 203 evaluates the access performance (performance related to access) of each storage device 30 provided in the data center 10 provided therein. For example, the inter-point delay evaluation value management unit 203 evaluates an access performance evaluation value (access evaluation value T (Mbps)) by executing a benchmark such as a disk load test on each storage device 30. Also good. The access evaluation value T is a value representing the time (access speed) required for accessing the file stored in the storage device 30 from the GW 402, for example.

  Next, the inter-point delay evaluation value management unit 203 measures the communication time between itself and the GW 402 of the data center 10 at each point. For example, the inter-point delay evaluation value management unit 203 may measure RTT (Round Trip Time) as a communication time by pinging the GW 402 of the data center 10 at each point. The inter-point delay evaluation value management unit 203 uses the RTT value as an access time to each data center 10 from a user terminal at a point where the data center 10 in which the inter-point delay evaluation value is provided is located.

Next, the inter-point delay evaluation value management unit 203 acquires an inter-point delay evaluation value for each data center based on the access evaluation value and the communication time. For example, the point-to-point delay evaluation value management unit 203 may calculate the response time RT for each data center using the following Equation 1, and obtain a score corresponding to the response time RT as the point-to-point delay evaluation value.
RT = SIZE ÷ (1024 ÷ RTT + T) (Formula 1)
In Equation 1, SIZE is a constant. The inter-point delay evaluation value management unit 203 sets a larger inter-point delay evaluation value (score) as the response time RT increases.

The inter-DC connection device 205 communicates with the inter-DC connection device 205 of another data center 10 when receiving an instruction to change the file arrangement destination by the arrangement destination determination device 50, thereby Rearrange. When the inter-DC connection device 205 receives an instruction to place a file placed in the data center 10 with which it is installed in another data center 10, the DC connection device 205 reads the target file from the storage device 30. Then, the inter-DC connection device 205 transmits the read file to the inter-DC connection device 205 of the data center 10 that is a new placement destination. Further, when the DC connecting device 205 receives a file from the DC connecting device 205 of another data center, the DC connecting device 205 records the received file in the storage device 30 of the data center 10 in which the DC connecting device 205 is provided.
Since the redirect device 401 and the GW 402 are devices that are not different from the conventional devices, a detailed description thereof will be omitted. The processing performed by the redirect device 401 and the GW 402 will be briefly described with reference to FIG.

FIG. 5 is a schematic block diagram illustrating a specific example of a functional configuration of the arrangement destination determination device 50. The placement destination determination device 50 includes a CPU, a memory, an auxiliary storage device, and the like connected by a bus, and executes a placement destination determination program. By executing the placement destination determination program, the placement destination determination device 50 includes a history information acquisition unit 501, an access history storage unit 502, an evaluation value acquisition unit 503, an inter-point delay evaluation value storage unit 504, an evaluation unit 505, and a determination unit 506. It functions as a device provided. Note that all or part of each function of the placement destination determination device 50 may be realized using hardware such as an ASIC, PLD, or FPGA.
Note that the function of the placement destination determination device 50 is not necessarily implemented in a single device. For example, the function of the placement destination determination device 50 may be distributed and implemented in a plurality of devices. Further, the function of the placement destination determination device 50 may be implemented in any one or a plurality of data centers 10.

The history information acquisition unit 501 communicates with the file arrangement optimization device 20 of each data center 10 and acquires the access history information recorded in each file arrangement optimization device 20. The history information acquisition unit 501 records the acquired access history information in the access history storage unit 502.
The access history storage unit 502 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The access history storage unit 502 stores access history information in each data center 10.

The evaluation value acquisition unit 503 communicates with the file arrangement optimization device 20 of each data center 10 and acquires a point-to-point delay evaluation value table stored in each file arrangement optimization device 20. The evaluation value acquisition unit 503 records the acquired inter-point delay evaluation value table in the inter-point delay evaluation value storage unit 504.
The point-to-point delay evaluation value storage unit 504 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The point-to-point delay evaluation value storage unit 504 stores a point-to-point delay evaluation value table in each data center 10. FIG. 6 is a diagram illustrating a specific example of the point-to-point delay evaluation value table stored in the point-to-point delay evaluation value storage unit 504. As illustrated in FIG. 6, the point-to-point delay evaluation value table stored in the point-to-point delay evaluation value storage unit 504 includes the point-to-point delay evaluation values acquired in the data centers 10 at a plurality of points.

  The uppermost record 61-1 of the point-to-point delay evaluation value table shown in FIG. 6 is the same as the point-to-point delay evaluation value table shown in FIG. That is, the uppermost record 61-1 in the inter-point delay evaluation value table shown in FIG. 6 is installed at each point (A, B, C, D,...) From the user terminal located at the A point. This represents a point-to-point delay evaluation value regarding a delay occurring between the data center 10 and the data center 10. The record 61-2 includes a point-to-point delay evaluation value relating to a delay occurring between the user terminal located at the point B and the data center 10 installed at each point (A, B, C, D,...). Represent. The record 61-3 stores a point-to-point delay evaluation value related to a delay occurring between the user terminal located at the point C and the data center 10 installed at each point (A, B, C, D,...). Represent. The record 61-4 stores a point-to-point delay evaluation value relating to a delay occurring between the user terminal located at the point D and the data center 10 installed at each point (A, B, C, D,...). Represent.

  From the above, in the inter-point delay evaluation value table shown in FIG. 6, the vertically arranged spot names (A, B, C, D,...) Represent the spots where the user terminal is assumed to be located. On the other hand, the point names (A, B, C, D,...) Arranged side by side represent points where the data center 10 storing the accessed file is located. For example, the evaluation value of the inter-point delay that occurs when accessing the file of the data center 10 located at the point A from the user terminal located at the point D is the numerical value indicated by the rectangle in the second column from the left in the fifth row from the top. 5 ".

  For each file, the evaluation unit 505 evaluates for each data center a delay evaluation value related to a delay that occurs in access from the user terminal when the file is arranged. FIG. 7 is a diagram illustrating a specific example of the evaluation content of the delay evaluation value. A record 62-1 in FIG. 7 is a diagram showing the evaluation result of the delay evaluation value for the file 0001. Assuming that the file 0001 is placed in the data center 10 at the point A, the delay evaluation value when an access similar to the access history (see FIG. 3) stored in the access history storage unit 502 occurs is 1 + 5 + 4 = 10 Is calculated. “1” to be added is a point-to-point delay evaluation value when the user terminal located at the point A accesses a file in the data center 10 at the point A. “5” to be added is a point-to-point delay evaluation value when the user terminal located at the point D accesses a file in the data center 10 at the point A. “4” to be added is a point-to-point delay evaluation value when the user terminal located at the point C accesses the file of the data center 10 at the point A. The evaluation unit 505 calculates a delay evaluation value as shown in FIG. 7 by performing such calculation for each file.

  The determination unit 506 determines the data center 10 that is the placement destination for each file based on the evaluation result of the evaluation unit 505. For example, the determining unit 506 determines, for each file, the data center 10 at the point where the delay evaluation value is minimum as the placement destination. The decision unit 506 notifies the decision result (file ID and identification information of the arrangement destination data center 10) to the data center 10 in which the file relating to the decision is arranged. Upon receiving the notification, the data center 10 reads the file arranged in itself and transmits the read file to the data center 10 of the new arrangement destination indicated by the determination result. When the data center 10 of the new placement destination receives the file, it records the received file in its own storage device 30.

  In the data distribution system configured as described above, it is possible to suppress a decrease in access quality caused by network delay. The details are as follows. In the data distribution system, the evaluation unit 505 evaluates the delay evaluation value for each data center with respect to the file (data) to be recorded. The delay evaluation value is a value representing an estimated value of the network delay caused by access from each user terminal when the file is arranged in a certain data center. Such a delay evaluation value is calculated based on the actual access history for each file and the evaluation value of the delay between points (inter-point delay evaluation value). Then, a file is arranged for the data center 10 having a small delay evaluation value. Therefore, it is possible to suppress a network delay caused by access to each file and to suppress a decrease in access quality.

  FIG. 8 is a diagram illustrating a specific example of the magnitude of the adverse effect on the data distribution system caused by the delay. Tier 1 represents a data center 10 that is not loaded with delay. Tier 2 represents the data center 10 loaded with a 20 millisecond delay. It can be seen that there is a difference of 10 times or more in reading time (Read) and writing time (Write) regardless of the file size. Thus, a delay of only 20 milliseconds greatly reduces the access quality. That is, in the data distribution system, even if the occurrence of delay is small, it will have a great adverse effect. In the above data distribution system, it is possible to suppress such a decrease in access quality.

  Further, the above data distribution system has the following effects. If the time required for accessing the file stored in each data center 10 from the inter-point delay evaluation value management unit 203 is measured, the network bandwidth may be compressed. For such a problem, the inter-point delay evaluation value management unit 203 determines the communication time between itself and the GW 402 of each data center 10 and the time required for accessing the file of each storage device 30 from the GW 402, respectively. Acquire and evaluate the inter-point delay evaluation value according to the result. Therefore, it is possible to prevent pressure on the network band. Furthermore, it is possible to clearly determine the location of the bottleneck. Therefore, provisioning becomes easy.

<Modification>
The determination unit 506 may be configured to determine an arrangement destination of each file arranged in the data center 10 for the data center 10 that satisfies a predetermined condition. Hereinafter, a specific example of such a configuration will be described.

FIG. 9 is a schematic block diagram illustrating a specific example of a functional configuration of a modification example (arrangement destination determination device 50a) of the arrangement destination determination device. The placement destination determination device 50a includes a determination unit 506a instead of the determination unit 506. The placement destination determination device 50 a includes a timing information storage unit 511.
The timing information storage unit 511 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The timing information storage unit 511 stores information related to the timing at which the determination unit 506a performs the process of determining the data center 10 that is the placement destination. FIG. 10 is a diagram illustrating a specific example of the timing information table stored in the timing information storage unit 511.

  The timing information table has a threshold, a cumulative value, and an execution prohibition time zone for each data center 10. The threshold value is a preset value. The accumulated value represents the accumulated value of the point-to-point delay evaluation value corresponding to the access that has occurred in the data center 10. The execution prohibition time zone represents a time zone in which execution of the processing instructing the data center 10 to change the file placement destination by the determination unit 506a is prohibited.

  Each time new access information is written in the access history storage unit 502, the determination unit 506a adds the inter-point delay evaluation value corresponding to the new access to the accumulated value. For example, when the newly written access information indicates that access has occurred from the user terminal located at the point D to the file 0001 arranged in the data center 10 at the point A, the determining unit 506a “5” is further added to the accumulated value “153” of the record whose value is “A”. When the accumulated value exceeds the threshold value, the determining unit 506a determines the data center 10 to be a new placement destination for each file placed in the data center. Then, the determination unit 506a notifies the data center 10 of the determined arrangement destination, and instructs to change the arrangement destination. However, when the time zone is an execution prohibition time zone, the determination unit 506a gives an instruction after the execution prohibition time zone has passed.

  FIG. 11 is a flowchart showing the flow of processing of the determination unit 506a in the modification. The determination unit 506a updates the accumulated value based on the newly written access information (step S101). Next, the determination unit 506a determines whether or not the updated accumulated value exceeds the threshold value (step S102). When the accumulated value does not exceed the threshold (step S102—NO), the determination unit 506a returns to the process of step S101. On the other hand, when the accumulated value exceeds the threshold (step S102—YES), the determination unit 506a determines whether or not it is the execution prohibited time zone (step S103). When it is the execution prohibition time zone (step S104-YES), the determination unit 506a waits until the execution prohibition time zone ends. On the other hand, when it is not the execution prohibition time zone (step S104—NO), the determination unit 506a instructs the data center 10 on the determined placement destination (step S105).

  According to the placement destination determination device 50a configured as described above, it is possible to preferentially distribute files for the data center 10 where access is concentrated. For this reason, it is possible to distribute the files before the access quality is significantly degraded, and to suppress the significant degradation of the access quality.

The inter-point delay evaluation value management unit 203 may repeatedly perform the inter-point delay evaluation value acquisition process at a predetermined timing. With this configuration, it is possible to maintain the information stored in the inter-point delay evaluation value storage unit 204 at a value that is more realistic.
Each data center 10 may be configured to store an arrangement destination table that represents identification information of files arranged in each data center 10. FIG. 12 is a diagram illustrating a specific example of the placement destination table. The arrangement destination table has identification information (file ID) of a file arranged in the data center 10 for each identification information (for example, a spot name) of the data center 10. In the example of FIG. 12, files 0001 and 0005 are arranged in the data center 10 located at the point A.

The determination unit 506 may determine the data center 10 that is the placement destination based on the delay evaluation value and other elements. The other element may be a value representing the free capacity in each data center 10, for example. FIG. 13 is a flowchart illustrating a specific example of the processing of the determination unit 506 configured as described above.
First, the determination unit 506 selects the data center 10 having the lowest delay evaluation value as the placement destination for the file to be processed (step S201). Next, the determination unit 506 determines whether or not the size of the file to be arranged fits in the free capacity of the selected data center 10. That is, it is determined whether there is a surplus resource in the selected data center 10 (step S202). When there is no surplus resource (step S202—NO), the determination unit 506 selects the data center 10 having the next lowest delay evaluation value as the placement destination after the previously selected data center 10 (step S201). The determination unit 506 repeats the process until the data center 10 having a surplus resource is selected in step S202.

  When there is a surplus resource in the selected data center 10 (step S202—YES), the determination unit 506 determines the selected data center 10 as an arrangement destination. Then, the data center 10 storing the file to be processed is instructed to transmit to the determined data center 10 (step S203). Then, the determination unit 506 updates the placement destination table (see FIG. 12) (step S204).

FIG. 14 is a diagram illustrating a specific example of a processing flow when a user terminal accesses a file. Next, a flow of processing when the user terminal accesses each file after the file placement destination is determined by the placement destination determination device 50 described above will be described.
First, the user terminal inquires a predetermined DNS about the nearest data center 10 (1). The DNS determines the location information of the user terminal based on the IP address assigned to the user terminal (2). Then, the DNS notifies the user terminal of the IP address of the data center 10 that is closest to the location information of the user terminal. For example, the DNS notifies the user terminal of the IP address of the data center 10 located in the same administrative division as the administrative division represented by the location information of the user terminal.

  Based on the notified IP address, the user terminal transmits an access request to the access target file to the data center 10 (3). When the file to be accessed is arranged in the data center 10 that has received the access request, the redirect device 401 does not execute the redirect process. In this case, access from the user terminal to the file recorded in the storage device 30 (storage) of the data center 10 is permitted (4).

  On the other hand, when the access target file is not arranged in the data center 10 that received the access request, the redirect device 401 refers to the arrangement destination table (see FIG. 12) and the access target file is arranged. The data center 10 is determined. Then, the redirect device 401 redirects to the data center 10 where the file to be accessed is arranged (5). By this redirection, the user terminal accesses the file to be accessed.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

DESCRIPTION OF SYMBOLS 10 ... Data center, 20 ... File arrangement optimization apparatus 201 ... Access history management part, 202 ... Access history storage part, 203 ... Inter-point delay evaluation value management part, 204 ... Inter-point delay evaluation value storage part, 205 ... Between DC Connection device, 30 ... storage device, 401 ... redirect device, 402 ... GW, 50, 50a ... placement destination determination device, 501 ... history information acquisition unit, 502 ... access history storage unit, 503 ... evaluation value acquisition unit, 504 ... point Delay evaluation value storage unit, 505... Evaluation unit, 506, 506a... Determination unit, 511.

Claims (4)

For the data to be recorded, an evaluation unit that evaluates for each data center a delay evaluation value related to a delay that occurs in accessing the data when the data is arranged;
A determination unit that determines a data center to which each data is to be arranged based on the delay evaluation value and the free capacity of each data center;
Equipped with a,
The determination unit determines whether the data can be stored in the data center based on the free capacity for each data center in ascending order of the delay evaluation value, and finds a data center capable of storing the data. in time, found disposed destination determining system that determines the data center to the data center as a placement destination of the data. A point-to-point delay evaluation value acquisition unit that acquires a point-to-point delay evaluation value related to a delay that occurs between a user terminal located at a certain point and each data center for each combination of data center and point;
A history information acquisition unit that acquires history information of access to each data from the user terminal;
Further comprising
The placement evaluation system according to claim 1, wherein the evaluation unit evaluates the delay evaluation value based on the inter-point delay evaluation value and the history information. For the data to be recorded, an evaluation step for evaluating for each data center a delay evaluation value relating to a delay that occurs in accessing the data when the data is arranged;
A determination step of determining a data center as a placement destination of each data based on the delay evaluation value and the free capacity for each data center;
I have a,
In the determining step, based on the free capacity of each data center, it is determined whether or not the data can be stored in the data center in ascending order of the delay evaluation value, and a data center capable of storing the data is found. An arrangement destination determining method for determining a data center that is found as a data center to be an arrangement destination of the data at a point of time . For the data to be recorded, an evaluation step for evaluating for each data center a delay evaluation value relating to a delay that occurs in accessing the data when the data is arranged;
A determination step of determining a data center as a placement destination of each data based on the delay evaluation value and the free capacity for each data center;
To the computer ,
In the determining step, based on the free capacity of each data center, it is determined whether or not the data can be stored in the data center in ascending order of the delay evaluation value, and a data center capable of storing the data is found. at the time was, the order to determine the found data center to the data center as a placement destination of the data the computer program.

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