JPS6310250A - Virtual logical volume management method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] In a virtual logical volume method that recognizes a collection of volumes that store a group of commonly used files as one virtual logical volume, when creating a file, the corresponding logical volume is By selecting constituent physical volumes approximately equally and distributing files to each physical volume, access distribution to each physical volume within a logical volume is achieved and access waiting times are reduced.

[Industrial application field]

The present invention relates to a volume management system, and particularly to improving access efficiency in a virtual logical volume system.

[Conventional technology]

The information processing system is equipped with auxiliary storage devices such as magnetic tape (MT) devices and magnetic disk devices (DASD), which are collectively managed by the job management section of the operating system (O8). There is.

That is, a variety of information is stored in the auxiliary storage device in one aggregate for each system-related file or business unit, and the location of these files, DASD space allocation, etc. is controlled by the job management section. Centrally managed.

Conventionally, the collection of the above information is one MT or one D.
Since it was large enough to fit into one physical volume such as an ASD, a plurality of information aggregates were actually stored in one physical volume.

However, in recent years, the amount of information has increased significantly, and a situation has arisen in which multiple volumes are required to accommodate one collection of information.As a result, even if a user only handles one collection of information, When operating multiple volumes, and when using multiple MTs, it is necessary to synchronize the MT mounts by mounting other volumes after completing the processing of the physical volume. It becomes necessary.

With conventional volume management methods, when a single information collection spans multiple volumes, the above-mentioned system operation and operational complexity arises, and this makes it difficult to automate and save labor in the operation of information processing systems. This was one of the hindrances.

Therefore, the present inventor previously proposed in Japanese Patent Application No. 61-5853 that a plurality of commonly used physical volumes can be virtually integrated into one.
proposed a virtual logical volume method that allows handling of individual logical volumes.

According to this method, volumes that store files that are commonly used, such as files that are used in the same job or system files that are used in conjunction, can be Multiple volumes can be handled as if they were one volume. Therefore, at least one physical volume that stores the above-mentioned commonly used file group is virtually treated as one logical volume,
A logical volume serial number is assigned to this virtual logical volume, and a sequence number is assigned to the physical volumes that make up the logical volume, and the correspondence relationship between the sequence number and physical machine number for each logical volume is determined. , and register it in the logical volume management table.

When accessing a file in a logical volume with such a configuration, for example, the logical volume management means provided in the job management section of the operating system refers to a catalog register (not shown) and determines whether the target file is stored. Read out the logical volume serial number that is
Next, the physical machine number of the first physical volume of this logical volume is read from the logical volume management table.

And the Polyneme Catalog (■TOC) provided in this
), reads necessary information such as the physical machine number and address of the volume where the target file is stored, and controls access to the target file accordingly.

As explained above, with this method, instead of being aware of volumes corresponding to physical machine numbers, you only need to be aware of virtual logical volumes that group multiple physical machine numbers.
This provides a more realistic environment for handling collections of information.

In this way, according to this method, even if there are multiple volumes used for one business, the user only needs to consider them as one logical volume, which greatly improves the operability of the system. improve.

However, in the past, there was no concept of treating a plurality of physical volumes as one logical volume, so naturally there is no management method that effectively utilizes the characteristics of the logical volume.

As a result, if one logical volume is configured from the beginning with multiple physical volumes at the time of system generation, conventional volume management functions will not be able to convert this logical volume into one large volume with multiple physical volumes connected in series. Manage it as if it were a volume. In other words, it is treated as if the capacity of the physical volume had increased. Therefore, when specifying an area to store a file or a library that is a collection of files, consecutive areas are allocated sequentially from the beginning of one logical volume.As a result, files may be unevenly distributed in a specific logical volume. Therefore, accesses will be concentrated on that volume.

Logical volumes are a method that treats multiple physical volumes virtually as if they were one volume, but each volume is accessed physically independently, so even if multiple physical volumes are the same, - Even if they belong to logical volumes, each of them can be physically accessed at the same time.

However, if a logical volume has a configuration in which multiple physical volumes are simply connected in series, that is, a configuration in which the physical volume is simply enlarged, files will be unevenly distributed in a specific volume, for example, the first volume, and access to that volume will be difficult. becomes concentrated. If access requests are concentrated on the same volume, all but one access request will be forced to wait. On the other hand, there are few access requests to other volumes. Therefore, unless conventional volume management is improved, the access efficiency of the logical volume method cannot necessarily be said to be high.

[Problem that the invention seeks to solve]

The reason why access requests are concentrated on the above-mentioned specific volume is because files are unevenly distributed in that volume.

Therefore, an object of the present invention is to improve access efficiency by distributing access by distributing files among a plurality of physical volumes that constitute a logical volume without unevenly distributing files in a specific volume.

[Means for solving problems]

In the virtual logical volume method, which treats a collection of multiple physical volumes that store a group of commonly used files as one virtual volume, when a file is created, the data stored in the above logical volume is A physical volume selection means is provided for selecting a physical volume in which a file is to be stored, based on file management information, so that the file is evenly placed in each physical volume forming a logical polyneme.

[For production]

Multiple files in the same physical volume cannot be accessed at the same time, so if files are stored in a specific physical volume, access requests will be concentrated on the same physical volume, and the order of access will be different. The probability of waiting increases. Therefore, by distributing files to each physical volume that constitutes a logical volume, access requests to each physical volume will be distributed, and the rate of waiting for access will be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of the above embodiment, in which 18 to 1i are physical volumes such as magnetic disk devices and magnetic tape devices, and A to E, which are a collection of these physical volumes, are used in common. A virtual logical volume that stores a group of files.

First, in preparation for using volumes, for logical volumes B, C, and D shown in the figure that you want to handle in common, specify the same logical volume serial number through the logical volume recognition means 4 and initialize them. I do.

Next, the job management unit 12 of 081i recognizes that the logical volumes having the same logical volume serial number are the same logical volume.

Recognition of logical volumes is normally executed when 081i is initially loaded and when installed into the system using a mount command, and it is determined whether there are logical volumes with the same serial number. If there is one, the physical volume with the lowest physical machine number is the first, and sequence numbers in the logical volumes are assigned in order.

The logical volume serial number and sequence number determined as described above and the physical machine number are registered in the logical polynym management table 5 in correspondence with each other.

As shown in FIG. 2, each logical volume A to E is provided with a file management information storage section 7 called a volume table of contents (VTOC). This includes management information for each file 31, 32 stored in the logical volume, ie, the sequence number 24 of the physical volume storing the file, the starting position of the file 23. File end position 22, identification name such as file name 21. and others [not shown] are recorded. This file management information is created using a recording area of a certain number of bytes for each file.

Conventionally, this was provided for each physical volume and recorded the management information of the files stored in that physical volume. , management information for the entire file stored in the logical volume is recorded.

An example of creating a new file 33 where two files 31 and 32 are already stored in the logical volume B shown in FIG. 1 will now be described with reference to FIGS. 1 and 2.

As seen in Figure 2, logical volume B consists of three physical volumes lb, lc, and ld, and as mentioned above, these physical volumes are assigned sequence numbers in order from the smallest physical machine number. 1.2.3 has been assigned. This logical volume B already has the name A.
Two files, AAAA and 8BCDE, are stored in the physical volumes 1b and 1c, respectively, and the various file management information described above is recorded in the illustrated file management information storage section 7. This file management information is recorded in the same way as shown when creating a new file.

Assume that you are trying to create a new file named XYZ.

The physical volume selection means 6 (see FIG. 1) refers to the file management information storage section 7 to check the storage status of existing files. In this example, files are stored in physical volumes 1b+lc with sequence numbers 1 and 2, but no files exist in physical volume ld. Therefore, the physical volume selection means 6 selects this physical volume ld and selects the corresponding sequence number 3.
is specified for file XYZ. This result name XY
The file 33 of Z is stored in the physical volume ld with sequence number 3, and its information (not shown) is recorded in the file management information storage section 7.

In this way, in this embodiment, the physical volume selection means 6
selects a physical volume to store the file to be created so that the file is almost evenly distributed among the physical volumes that make up the logical volume.

The method for selecting physical volumes for distributing files does not need to be particularly limited, but can be implemented, for example, as follows.

That is, when creating a file, the sequence number storing the existing file is read from the file management information storage section 7, and the sequence number with the least frequency of occurrence is assigned to the newly created file, thereby assigning the file to each physical volume. Can be distributed.

Also, when starting up the system, the file management information storage unit 7
, prepare an area corresponding to the number of files that can be accommodated, and cyclically write sequence numbers from the smallest to the largest value in each sequence number section. At this time, the file does not exist yet, so items other than the sequence number remain blank.

If you do this, and when creating a file, use it from the beginning of the file management information storage section 7 and automatically allocate the physical volumes recorded there, the file will be stored in each physical volume in order. As a result, the files will naturally be distributed.

〔Effect of the invention〕

As described above, according to the present invention, files are distributed and stored in each physical volume that constitutes a logical volume, so access is also distributed to each physical volume, and therefore the access efficiency of the logical volume is improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a virtual logical volume management system for explaining the operation of the above embodiment. In the figure, 1a+lb+...1i are various physical volumes, 6 is a physical volume selection means, 7 is a file management information storage unit (VTOC), 31.32.33 are files, A, B,..., E indicates a logical volume.

Claims (1)

[Claims] At least one physical volume (1a, 1b, . . . , 1i) that stores a group of commonly used files is virtually integrated into one logical volume (A, B, . . ., E), assigning one logical volume serial number to each logical volume, and assigning a sequence number to each physical volume constituting the logical volume for each logical volume. , in a virtual logical volume system comprising, for each logical volume, a file management information storage section (7) that records the identification name of the file stored in that logical volume and the sequence number of the physical volume in which the file is stored. A physical volume selection means (6) is provided for selecting a physical volume to store the file when creating the file, and when creating the file, the physical volume selection means (6) selects the file management information storage section of the corresponding logical volume (B). From (7), the sequence numbers of the physical volumes (1b, 1c, 1d) that store existing files are checked, and the physical volumes that store the files are selected so that the sequence numbers appear approximately evenly. Features a virtual logical volume management method.