Browse Prior Art Database

A method to keep good response time of on-line system on multi system environment

IP.com Disclosure Number: IPCOM000013610D
Original Publication Date: 2000-May-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Abstract

Disclosed is a method that reduces time to wait for recovery of a complex file system used by mission critical on-line system in multi-system environment.

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  A method to keep good response time of on-line system on multi system environment

Disclosed is a method that reduces time to wait for recovery of a complex file
system used by mission critical on-line system in multi-system environment.

When read or write operation is requested but the response from disk is not
returned within an expected period, it is called I/O timeout.

A complex file system may have one or more mirrored files or spare files which
are prepared for disk system failure. And such file system usually gets
exclusive control to access the file and keeps data integrity. When an error
occurs on such file system, a mirrored file takes over failed file and the
mirrored file becomes a main file immediately. But in case of the error is not
notified to the I/O request system, I/O request system has to wait recovering
the defected file. A mission critical on-line system cannot wait the recovery
of failed file. If on-line system detects I/O timeout against a complex file
system and it is caused by an error, on-line system can detach the defected
file and continues processing. But, usually on-line system cannot determine
whether it is caused by a physical error or other reason, for example, another
system is reading or writing that file with having exclusive control.

With this disclosed method, on-line system can determine timeout reason
correctly and degradation of transaction response time is minimized.

When I/O timeout is caused by an error, this disclosed method works a...