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Improved Flash Copy for Non-Cache Storage System

IP.com Disclosure Number: IPCOM000249424D
Publication Date: 2017-Feb-27
Document File: 4 page(s) / 95K

Publishing Venue

The IP.com Prior Art Database

Abstract

Non-Cache storage system could statistic and firstly deal with the grains with the high write frequency to improve Flash Copy I/O write performace

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Improved Flash Copy for Non-Cache Storage System

Background:

Flash Copy provides the semantics of a point in time copy by using an indirection layer which intercepts I/Os targeted at both the source and Target

Virtual Disks. The indirection layer makes a decision about each I/O. Where writes occur to source to an area (grain) which has not yet been copied, these will

usually be stalled whilst a copy operation is performed to copy data from the source to the target, to maintain the illusion that the target contains its own

copy.

In a non-cache storage system, such I/O stall will reduce the I/O write performance.

Novel Point: In storage free time, I/O statistics module could find out high write frequency grains during background copy. Those grains with high write frequency will

be copied to target preferentially while next flash copy period.

Advantage: Increase write performance for non-cache storage system.

Description: During background copy of flash copy, where writes occur to source to an area (grain) which has not yet been copied, these will usually be stalled

whilst a copy operation is performed to copy data from the source to the target. In a non-cache storage system, such I/O stall will reduce the I/O write performance.

As flash copy are used to configured as periodic execution (e.g. 24:00 every day), the write frequency of the grains during background copy could be

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statistics in free time. The improved flash copy will firstly copy the grain with high write frequen...