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Defragmentation improvement on RAID disk device

IP.com Disclosure Number: IPCOM000011893D
Original Publication Date: 2003-Mar-24
Included in the Prior Art Database: 2003-Mar-24

Publishing Venue

IBM

Abstract

Disclosed is a idea for shortening the processing time of defragmentation for RAID disk devices except RAID-0/1.Conventionally, defragmentation is realized by moving data to optimal position in disk device.In non-RAID and RAID-0/1 disk devices, as one of the effects of defragmentation, I/O response improves.It is because data become close each other physically.However, in RAID disk devices except RAID-0/1, the improvement of I/O response is not supposed to exist.It is because RAID mechanism has managed the physical position on a disk device, and consequently, it is because data don't necessarilly become close each other physically.On this idea, it is enabled to carry out defragmentation without moving data.It is realized by newly introducing a data position managed table on RAID disk devices.Consequently, the processing time of defragmentation can be shortened sharply.From here, "RAID disk device" points out RAID except RAID-0/1.