JP2003015917A - Data migration processing method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the free space in an upper storage device from becoming insufficient by shortening the time taken for migration processing. SOLUTION: A migration candidate retrieval processing part 1 is executed, at every given period, collects file information on every file in a disk device 4, sorts the collected file information according to the migration priority, produces a list of sorted file information, and outputs a migration candidate list 3. A migration processing part 2 is initiated asynchronously to the migration candidate retrieval processing part 1, inputs respective pieces of the file information from the migration candidate list 3 in the disposed order, and moves, regarding files that have not been referred to or updates after the collection of the file information, the corresponding file to a magnetic tape device 5 until a free space of a given capacity is secured in the disk device 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data migration method, which is a technology for managing hierarchical storage devices, and more particularly to a data migration processing method performed to secure a free area in an upper storage device.

[0002]

2. Description of the Related Art A file on a disk is moved to a lower storage device such as a magnetic tape device when the remaining amount of free space on the upper storage device, which is a main file storage location such as a disk device, becomes small. Migration processing is performed. In the conventional migration process, as described in Japanese Patent Laid-Open No. 5-158760, file information of all files in a directory is collected after the migration process is started and the file update date, reference date, or file size is used. Files are sorted in descending order of priority to be migrated to the magnetic tape device, a migration target file list is created, the file data is transferred to the magnetic tape device in the order of this list, and then the corresponding file on the disk device is The data in the file was deleted to secure a free area in the disk device.

[0003]

In a large-scale system in which the number of files reaches several million, a process of collecting file information of all files and migration based on file update date, reference date or file size are performed. Since the sorting process that determines the order takes several hours, in the above-mentioned conventional technique, when a large amount of data is output to the disk device in a short time, the free space cannot be secured by the migration process in time and the disk device becomes empty. Out of space,
There was a problem that it hindered the operation of the system.

An object of the present invention is to provide a method for reducing the time required for migration processing,
It is another object of the present invention to provide a method for preventing the upper storage device from running out of free space.

[0005]

In order to achieve the above-mentioned object, in the data migration processing method of the present invention, a migration process for collecting time-consuming file information and a sorting process for deciding the order of files to be migrated are performed. The candidate search processing procedure is separated from the migration processing procedure. The migration candidate search processing procedure is started asynchronously with the migration processing procedure and at a predetermined cycle.
Create a migration candidate list. In the migration processing procedure, file information records are input one by one from the migration candidate list created in advance, and a free space of a predetermined capacity is created in the upper storage device for files that have not been referenced or updated since the file information was collected. The corresponding file on the upper storage device is moved to the lower storage device until it is secured. By such migration processing,
The above object is achieved.

[0006] The migration process transfers files to the lower storage device in order from a file that exists in the upper storage device and has not been used for a long time, and is accessed between the time when the migration candidate list is created and the time when the migration process is performed. Files to be migrated can be confirmed by excluding the files that have been migrated.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the components of the present embodiment and the overall processing flow. The system is activated in a predetermined cycle and outputs a candidate list of files that can be migration targets from all files on the disk device 4, and a migration candidate output by the migration candidate search processing unit 1. It is composed of a migration processing unit 2 which inputs the list 3 and migrates files on the disk device 4 to the magnetic tape device 5 until a necessary free space is secured.

The migration candidate search processing section 1 includes a file information collecting section 11 for collecting file information of all files on the disk device 4, a file sorting section 12 for deciding a migration order based on the collected file information, The sorted file information list is roughly classified into a list output unit 13 that outputs it as a migration candidate list 3 at a predetermined position on the disk.

The migration processing section 2 reads the file information records of the migration candidate list 3 one by one, and judges whether or not the corresponding file is a migration target file based on the input file information record. If the file is a migration target file, the migration processing unit 2 that migrates the corresponding file on the disk device 4 to the magnetic tape device 5
2. The termination determination unit 23 determines whether or not the total of free areas secured by migration has reached the required free area size. If the end determination unit 23 determines that the free space reaches the required free space, the migration process ends; otherwise, the process returns to the list input unit 21.

The migration candidate search processing unit 1 and the migration processing unit 2 are programs that are stored and executed in the memory on the electronic computer. The disk device that stores the migration candidate list 3, the disk device 4, and the magnetic tape device 5 are storage devices that are connected to this computer. Instead of the magnetic tape device 5, a large-capacity disk device may be used.

FIG. 2 is a flowchart showing the flow of processing of the migration candidate search processing unit 1. Since the migration candidate search processing unit 1 needs to operate prior to the migration process, the migration candidate search processing unit 1 is periodically (for example, 1 day per day) at intervals shorter than the interval at which the migration process is activated.
It is started at times, such as at night when the load is low.

When the migration candidate search processing unit 1 is activated, the file information collecting unit 11 collects the file information of all files on the disk device 4 in step 110,
For each file, a file information list in which the file information of the four items of the last update date, the last reference date, the file size, and the directory position information is one record is created. The directory location information includes the file name. It should be noted that the method of collecting the file information may be a commonly used method.

In step 120, the file sorting unit 12
For each record of the file information list created in step 110, the priority to be the migration target is calculated according to a previously defined calculation formula, and the records on the file information list are sorted in descending order of priority. The formula for calculating the priority is the last update date of the file, the last reference date,
It is a function that uses at least one of the three elements of the file size as a variable, and can take any function form that monotonically increases with respect to the last update date and the last reference date. The calculation formula of the priority may be a commonly used calculation formula.

In step 130, the list output section 13 outputs the file information list sorted in step 120 as a migration candidate list 3 to a file accessible by the migration processing section 2, and the migration candidate search processing section 1 is terminated.

FIG. 3 is a flow chart showing the flow of processing of the migration processing unit 2. The migration processing unit 2 is activated by a program such as an operating system that automatically detects that the free space of the disk device 4 has fallen below a predetermined value, and is passed the free space size to be secured as an argument. As a method of starting the migration process, there are other methods such as a method of starting at a predetermined cycle regardless of the free area of the disk device, and a method of starting by executing a command after the user or system administrator refers to the free area capacity of the disk device 4. You may use.

When the migration processing unit 2 is activated, the list input unit 21 inputs the file information of the migration candidate files from the files of the migration candidate list 3 one by one in the order in which they are arranged in step 210.

Step 220 of the migration processing section 22
Then, it is checked whether the last update date and the last reference date of the file indicated by the directory position information in the input record match the information in the record. If they match, it means that the migration candidate search processing unit 1 has not created a migration candidate list 3 and the file has not been referenced or updated.
The file is determined to be a migration target file and the process proceeds to step 221. If they do not match,
This indicates that the migration candidate search processing unit 1 has referred to or updated the file after the migration candidate list 3 was created, and the file is not the target of migration.
The process proceeds to the end determination unit 23 of 0.

Step 221 of the migration processing section 22
Then, the data of the corresponding file is read from the storage location of the disk device 4 indicated by the directory position information of the record input in step 210 and migrated to the magnetic tape device 5.

Step 222 of the migration processing section 22
Then, the file size of the file migrated in step 221 is added to the total value of the secured free area.

At step 230, it is checked whether or not the total value of the free areas secured by the migration by the end judging section 23 reaches the free area size desired to be secured, which is given at the start of the migration processing section 2. If yes, the migration processing unit 2 is terminated, and if not, the process returns to the list input unit 21 of step 210 to input the file information record of the next migration candidate file. Note that after the migration processing unit 2 once uses the migration candidate list 3, the migration candidate list 3 is deleted from the disk.

From the above description, the migration candidate search process for selecting a migration target file, which takes time, is separated from the migration process, and the time required for the migration process is shortened.

In the prior art, since the migration candidate search process and the migration process are performed after the reduction of the free space of the disk is detected, the migration candidate search process takes time, and the free space of the disk may not be secured in time. In the present embodiment, the total processing time of the migration candidate search processing unit 1 and the migration processing unit 2 is almost the same as the conventional one, but if only the migration processing unit 2 is executed after detecting the reduction of the free space of the disk. Since it is good, the time to secure free space on the disk is shortened,
Failure due to insufficient free disk space is prevented. However, it is necessary for the migration candidate search processing unit 1 to regularly output and prepare the migration candidate list 3 so that the migration processing unit 2 can always process the latest migration candidate list 3.

[0024]

As described above, according to the present invention, since the time-consuming migration candidate list creation process is excluded from the migration process main body, the time required for the migration process is the write time to the lower-level storage device. It is almost the same, and it is possible to shorten the time from when the reduction processing of the free area of the upper storage device is detected and the migration processing is started until the free area of the upper storage device is secured by the migration processing. Along with this, it is possible to prevent a failure that the free space of the upper storage device runs short during the migration process.

[Brief description of drawings]

FIG. 1 is a block diagram showing components constituting an embodiment and an overall processing flow.

FIG. 2 is a flowchart showing a processing flow of a migration candidate search processing unit 1 according to the embodiment.

FIG. 3 is a flowchart showing a processing flow of a migration processing unit 2 of the embodiment.

[Explanation of symbols]

1: Migration candidate search processing unit, 2: Migration processing unit, 3: Migration candidate list, 4: Disk device, 5: Magnetic tape device, 11: File information collecting unit, 12: File sorting unit, 13: List output Part, 2
1: List input section, 22: Migration processing section, 23:
End judgment part

Claims (4)

[Claims] 1. A free space on the first storage device by moving a part of a file on the first storage device to a second storage device according to the status of a free space on the first storage device. In the data migration processing method for increasing the area, as a migration candidate search processing procedure started at a predetermined cycle, file information is collected from each file on the first storage device, and the file information is set as a migration priority. According to the above, the procedure of creating and outputting a list of the arranged file information is performed according to the following, and each of the file information from the list is used as a migration processing procedure that is started asynchronously with the migration candidate search processing procedure. For each file that has not been referenced or updated since the file information was collected. Data migration processing method characterized by the steps of moving the appropriate file on the first storage device to the create the room of a predetermined capacity on the device to the second storage device. 2. The data migration processing method according to claim 1, wherein the migration processing procedure is started when it is detected that the free space of the first storage device falls below a predetermined value. . 3. A computer according to claim 1, wherein a part of a file on the first storage device is moved to a second storage device, and the first storage device is moved to the second storage device. A program for executing a data migration process for increasing the above free area, which is a procedure for collecting file information from each file on the storage device of the younger brother 1 as a migration candidate search process procedure,
The procedure of arranging the file information according to the priority of migration and the procedure of creating and outputting a list of the arranged file information are executed, and each of the file information is arranged from the list as a migration processing procedure. The procedure of inputting in order, and corresponding files in the first storage device until a free space of a predetermined capacity is secured in the first storage device for files that have not been referenced / updated after the collection of the file information. A program for executing a procedure for moving a file to the second storage device. 4. The program according to claim 3, wherein the migration candidate search processing procedure is executed every predetermined period, and the migration processing procedure is executed asynchronously with the migration candidate search processing procedure. .