JPH10240632A - On-line exchange method for external storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of realizing the on-line exchange of the external storage devices of different physical block sizes without the need of interrupting a program processing. SOLUTION: The external storage device of an active system to be exchanged is changed to a standby system, an input/output request to the device is inhibited (1) and the external storage device is physically exchanged with a new external storage device (2). Thereafter, the physical block size is obtained (3), the conversion processing of a logical block size (virtual block size) and the physical block size is performed, the information of the continuously used external storage device is copied to the exchanged external storage device (4), it is incorporated into a system (5) and thus, the on-line exchange is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for online replacement of an external storage device in an information processing system having a multiplexed external storage device and a control program therefor.

[0002]

2. Description of the Related Art In recent years, the development of external storage devices has been accelerated, and high-performance devices have been developed. However, since the hardware mechanisms are changed, they need to be replaced periodically. Further, in a system such as an electronic exchange, a method of multiplexing an external storage device to have a redundant configuration is adopted in order to guarantee high system reliability and uninterrupted service.

[0003] As an on-line exchange method of an external storage device, for example, "new edition original CTRON large system 3 input / output control interface device multiplexing function (member device copy)"
(Ohm Co., Ltd.), a method of multiplexing and defining an external storage device, and copying the information of the active external storage device to the spare external storage device while executing the input / output request from the online software. Has been proposed.
Further, "Online capacity expansion method of external storage device" (Japanese Patent Application No. 7-47306) proposes a method of online replacement of an external storage device when the storage capacity of the external storage device is changed.

[0004]

However, in the conventional methods described above, the hardware configuration including the physical block size of the external storage device is assumed to be the same between the active system and the standby system. When the physical block size of the external storage device is changed by exchanging the standby system and the active system, it is necessary to change a control program (driver) for controlling input / output requests to the external storage device. However, there is a problem that the change of the program requires the interruption of the program processing and the interruption of the service.

An object of the present invention is to provide a method capable of realizing online exchange of external storage devices having different physical block sizes without changing drivers, that is, without interrupting program processing.

[0006]

According to the present invention, in order to solve the above-mentioned problems, one of a plurality of multiplexed external storage devices constituting a working system and a standby system is replaced with another external storage device. In an external storage device online replacement method for performing online device replacement between the replaced external storage device and a continuously used external storage device, a block size for obtaining a physical block size from a plurality of multiplexed external storage devices An obtaining step, a block size storing step of storing the obtained physical block size, and an information copying step of copying information of the external storage device which is continuously used based on the stored physical block size to the replaced external storage device. It is characterized by having.

According to the above configuration, the physical block size of the external storage device is obtained and stored, and information is copied between the external storage devices multiplexed on the basis of the physical block size. It is possible to exchange devices between external storage devices of different sizes, process input / output requests corresponding to the physical block size of the replaced external storage device, and multiplex information between external storage devices of different physical block sizes. And parallel processing of input / output requests from online software becomes possible, and online exchange of external storage devices having different physical block sizes can be realized without changing drivers, that is, without interrupting program processing.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows an example of an information processing system to which the present invention is applied. In the drawing, reference numeral 1 denotes hardware, 2 denotes a hardware interface, and 3 denotes an O.
S and 4 are application programs.

The hardware 1 includes a well-known processor, a communication system, and the like, in addition to an external storage device to which the present invention is applied. The hardware interface 2 is, for example, an SC
A standard interface such as an SI interface is assumed. In this interface, although commands are standardized, the physical block size differs for each hardware.

[0010] As OS3, here, IROS (Interf Interface) which is an OS interface specification developed / released by NTT.
ace for Realtime Operating Systems)
It is assumed that a hierarchical structure including one interface 31, an S2 interface 32, a basic OS 33, and an extended OS 34 is provided.

The S1 interface 31 is a multi-vendor interface that hides differences in hardware between vendors and enhances portability of higher-level software. The S1 interface 31 is provided by a basic OS 33 including a kernel program, an input / output control program, and the like. You. In the S1 interface 31, a logical block (variable in size) is defined in order to provide the same software interface even when the hardware interface is changed by replacing the external storage device.

The S2 interface 32 is a service layer (such as an application program) which is a higher-order service layer.
, For logically providing resources such as communication lines, and is provided by the extended OS 34 including a file management program, a process management program, and the like.

A procedure for replacing the external storage device between the active system and the standby system according to the present invention will be described below in detail with reference to the sequence shown in FIG. The replacement of the external storage device is performed according to the following (1) to (4).

Device disconnection processing In response to a request for "priority member device switching" by higher-level software, the active external storage device to be replaced is changed to a standby system, and then the external storage device to be replaced in response to a "device disconnection" request. The state shifts to a state in which an input / output request to the server is not accepted.

Replacement of External Storage Device Physical replacement (replacement) of an external storage device with a new external storage device is performed.

Acquisition of physical block size Upon a system call (volume deletion instruction) issued from the extended OS, the driver issues a SCSI command (DM
R command) is issued to the replaced external storage device, and the physical block size is obtained.

Restoration Processing The driver stores the physical block size acquired corresponding to the multiplexed external storage device as internal data (device control block), and performs logical block size (virtual block size) and physical Used for conversion to block size. As a result, information can be copied between external storage devices having different physical block sizes.

Specifically, as shown in FIG. 3, assuming that the physical block size of the active external storage device 11 is b1 and the physical block size of the replacement external storage device 12 is b2, the copying process is not performed. The following processing is performed.

(1) Securing n bytes as the copy buffer 13 At this time, n is a common multiple of b1 and b2. (2) The information of the number of n / b1 physical blocks from the head block of the active device 11 is read out to the copy buffer 13. (3) Write the contents of the copy buffer 13 to the n / b2 physical block from the head block of the standby system device 12. (4) If information to be copied remains, the copy position is moved, and the processes of (2) and (3) are repeatedly executed. (5) Release the copy buffer 13.

Incorporation The external storage device is started to be duplexed in response to a request for “device installation” by the host software, and the replaced external storage device is changed to the active system in response to a request for “priority member device switching”. The work ends.

[0021]

As described above, according to the present invention,
After replacing any of the multiplexed external storage devices constituting the active system and the standby system with another external storage device,
In the external storage device online replacement method for performing online device replacement between the replaced external storage device and a continuously used external storage device, a block size acquisition for acquiring a physical block size from a plurality of multiplexed external storage devices A step of storing the obtained physical block size, and a step of copying information of the external storage device that is continuously used based on the stored physical block size to the replaced external storage device. With this configuration, online exchange of external storage devices having different physical block sizes can be realized without changing the driver, that is, without interrupting the program processing.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an information processing system to which the present invention is applied.

FIG. 2 is a sequence diagram showing an example of an embodiment of an online storage device exchange method according to the present invention;

FIG. 3 is an explanatory diagram showing how information in an active external storage device is copied to a standby external storage device using a copy buffer;

[Explanation of symbols]

1 ... hardware, 2 ... hardware interface,
3 OS, 4 application programs, 11, 1
2: external storage device, 13: copy buffer, 31: S1
Interface 32, S2 interface 33 Basic OS 34 Extended OS

Claims (2)

[Claims] After replacing one of a plurality of multiplexed external storage devices constituting an active system and a standby system with another external storage device, the replaced external storage device and an external storage device that is continuously used are replaced. Acquiring a physical block size from a plurality of multiplexed external storage devices, and a block size for storing the acquired physical block size. A method for online replacement of an external storage device, comprising: a storage step; and an information copying step of copying information of an external storage device that is continuously used based on the stored physical block size to the replaced external storage device. . 2. A copy buffer having a size equal to a common multiple of a physical block size of an external storage device being continuously used and a physical block size of a replaced external storage device is secured, and the size of the copy buffer is continued as a unit. 2. The method according to claim 1, further comprising an information copying step of repeatedly copying information in the used external storage device to the replaced external storage device.