JPH096677A - Write synchronous system - Google Patents

Abstract

PURPOSE: To secure the write synchronous against an optional extent of a disk through a program at an optional time point. CONSTITUTION: When the write synchronous is requested by an application program 2 of a host computer 1 in a write synchronous macro mode, a write synchronous means 4 of an operating system 3 issues a write synchronous command to a disk subsystem 5 to designate an extent and waits for an operation that writes the data which are recorded in a cache 7 but not reflected yet on a disk 8. A disk processor 6 of the system 5 receives the write synchronous command and reflects the unupdated data stored in the cache 7 on the disk 8 in a designated extent to report the write end to the computer 1. Receiving the report, the means 4 notifies the program 2 of the end of the write synchronous.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk cache system in which a host computer is connected to a disk subsystem that has a cache in a disk processing device and performs input / output with a disk via the cache. The present invention relates to a write synchronization method for a disk subsystem having a write cache function.

[0002]

2. Description of the Related Art In a disk subsystem having a write cache function, a write completion report is notified to a host computer when update data is recorded in a cache, and update data is written to a disk asynchronously by a disk processor. It is being appreciated. Therefore, when there is a cache failure, it is difficult to determine up to which point the data is correctly reflected on the disk.

Therefore, for example, Japanese Patent Laid-Open No. 59-1532
In the conventional disk cache system disclosed in Japanese Patent Publication No. 050, the update data recorded on the cache for the extent of the disk requested by the program but not reflected on the disk (hereinafter referred to as unreflected data). In order to guarantee that the data has been written to the disk, the unreflected data is reflected on the disk according to a specific command (COMMIT command) issued in a logical completion unit of the program, and the operation of the program and the contents of the disk are reflected. I was trying to stay in sync.

[0004]

In the conventional write synchronization system described above, the issuance timing of the specific command for reflecting the unreflected data in the cache to the disk is limited to the logical completion unit of the program. However, there is a problem that there is a limit to the time when the program and the contents of the disc can be synchronized.

Further, there is a problem that the extents of the disk which can be write-synchronized are only the extents updated by the program.

In view of the above points, an object of the present invention is to provide a write synchronization system which allows a program to perform write synchronization with an arbitrary extent of a disk at an arbitrary time.

[0007]

The write synchronization system of the present invention is a disk in which a host computer is connected to a disk subsystem that has a disk processing device and has a cache for inputting / outputting data from / to the disk via the cache. In the cache system, the program on the host computer is provided with a write synchronization macro that requests write synchronization to any extent of the disk at any time, and is provided in the operating system on the host computer. Unreflected data recorded in the cache but not reflected on the disk by issuing an extent-specified write synchronization command to the disk subsystem when write synchronization is requested from the program by the write synchronization macro. Written on disk And a disk processing unit that receives the write synchronization command and reflects the unupdated data on the cache in the designated extent to the disk to report the write completion to the host computer. .

[0008]

According to the write synchronization system of the present invention, the write synchronization means provided in the operating system on the host computer writes the extent to the disk subsystem at the time when the program requests the write synchronization by the write synchronization macro. Issue a command and wait for unreflected data recorded on the cache but not reflected on the disk to be written to the disk,
The disk processing device receives the write synchronization command, reflects the unupdated data on the cache in the designated extent on the disk, and reports the write completion to the host computer.

[0009]

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a disk cache system to which a write synchronization system according to an embodiment of the present invention is applied. In this disk cache system, a host computer 1 and a disk subsystem 5 are connected to each other to form a main part.

The host computer 1 is equipped with an application program 2 and an operating system 3 including a write synchronizing means 4.

The disk subsystem 5 has a cache 7
And a plurality of disks 8.

Referring to FIG. 2, a channel command for write synchronization (hereinafter referred to as a write synchronization command) issued to the disk subsystem 5 by the write synchronization means 4 identifies a volume of the disk 8. It is composed of a device identification number and a set of start addresses and end addresses of one or more extents (hereinafter referred to as extent entry).

Referring to FIG. 3, the process of the write synchronization means 4 is a file unit write synchronization determination step S101.
A file extent start / end address acquisition step S102, a volume unit write synchronization determination step S103, a volume extent start / end address acquisition step S104, an extent designation write synchronization command issue step S105, and a write end report presence / absence determination step S106. And a write synchronization completion notification step S107.

Referring to FIG. 4, the processing when the disk processing apparatus 6 receives a write synchronization command specifying an extent is the first extent entry point step S20.
1 and extent entry end determination step S202
And extent non-reflected data presence / absence determination step S20
3, an extent unreflected data disk reflection step S204, a next extent entry point step S205, and a write end reporting step S206.

Next, the operation of the write synchronization system of the present embodiment configured as described above will be described.

When it becomes necessary for the application program 2 to perform write synchronization with respect to an arbitrary number of arbitrary extents of the disk 8, the application system 2 provides the operating system 3 with a write synchronization macro for performing write synchronization in file units or volume units. It is issued to request write synchronization and suspends the processing temporarily.

In the operating system 3, when the write synchronization macro is received from the application program 1, the write synchronization means 4 determines whether it is the file-unit write synchronization (step S101). The start address and end address of the extent of the file managed by the operating system 3 are acquired (step S10).
2) Issue a write synchronization command specifying the extent to the disk subsystem 5 (step S10).
5).

If it is not the file-unit write synchronization in step S101, the write synchronization means 4 determines whether it is the volume-unit write synchronization (step S10).
3) In the case of volume-unit write synchronization, the start address and end address of the extent of the volume managed by the operating system 3 are acquired (step S104), and a write synchronization command specifying the extent is sent to the disk subsystem 5. It is issued (step S105). If it is not the volume-unit write synchronization in step S103, the write synchronization means 4 immediately ends the processing.

When the disk subsystem 5 receives a write synchronization command specifying an extent from the host computer 1, the disk processing device 6 points to the first extent entry (step S201) and determines whether the extent entry has ended. Yes (step S202). If the extent entry has not ended, the disk processing device 6 refers to the information of unreflected data in the cache 7 managed by the disk processing device 6 itself, and refers to the start address and end of the extent entry pointed to. It is determined whether there is unreflected data in the extent indicated by the address (step S
203). If there is unreflected data, the disk processing device 6
Reflects the unreflected data of the extent on the disk 8 (step S204). If there is no unreflected data,
Step S204 is skipped.

Next, the disk processing device 6 points to the next extent entry (step S20).
5), control is returned to step S202, and step S20
2 to S205 are repeated. Then, when the extent entry ends in step S202, the disk processing device 6 reports the end of writing to the host computer 1 (step S206) and ends the processing.

In the host computer 1, when the write completion report is received from the disk subsystem 5 (Yes in step S106), the write synchronization means 4 notifies the application program 2 that the write synchronization is completed (step S107). , The process ends.

When the operating system 3 is notified that the write synchronization has been completed, the application program 2 restarts the operation that was temporarily interrupted.

[0024]

As described above, the present invention provides a write synchronization macro for requesting write synchronization to an arbitrary extent of a disk at an arbitrary time in a program, so that the program can write a disk at an arbitrary time. There is an effect that write synchronization can be taken for any extent.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a disk cache system to which a write synchronization method according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a data structure of a write synchronization command issued by a write synchronization means in FIG.

FIG. 3 is a flow chart showing a process of a write synchronization means in FIG.

FIG. 4 is a flowchart showing a process of the disk processing device in FIG.

[Explanation of symbols]

 1 host computer 2 application program 3 operating system 4 write synchronization means 5 disk subsystem 6 disk processor 7 cache 8 disk

Claims (3)

[Claims] 1. A disk cache system in which a host computer is connected to a disk subsystem that has a cache in a disk processing device and performs input / output with a disk via the cache, wherein a program on the host computer is arbitrary. At the point of time, a write synchronization macro that requests write synchronization to any extent of the disk is provided, and the program is requested to perform write synchronization by the write synchronization macro provided in the operating system on the host computer. At this point, a write synchronization command for issuing an extent-specified write synchronization command to the disk subsystem, and waiting for the unreflected data recorded in the cache but not reflected on the disk to be written to the disk , Write synchronization method characterized by having a said disk processing apparatus unupdated data in the cache in the extent specified receiving said write sync command to reflect the disk reports write completion to the host computer. 2. The write synchronization method according to claim 1, wherein the write synchronization command can simultaneously request write synchronization for a plurality of extents. 3. The write synchronization method according to claim 1, wherein the write synchronization command can request write synchronization in file units or volume units.