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Method for enhancing the allocation policies of a logical volume.

IP.com Disclosure Number: IPCOM000021964D
Original Publication Date: 2004-Feb-17
Included in the Prior Art Database: 2004-Feb-17
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Abstract

Method for enhancing the allocation policy of a volume manger so that parts of logical volumes or whole logical volumes are allocated to different media.

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Method for enhancing the allocation policies of a logical volume .

Disclosed is a method for enhancing the allocation policies of a volume manager to allow the volume manger to automatically allocate space within one or more logical volumes on different physical media to increase throughput. Today some volume managers support allocation polices on mirrored logical volumes that cause different mirrors of a logical volume to be allocated on different physical media. This prevents the logical volume from going off-line by insuring that the mirrors are on different media so the failure of one disk does not cause loss of access to part of the logical volume. Different physical media could be established at the LUN level, media location, power domain of the media or the media could be subdivided into regions.

We propose automatic allocations within a single logical volume such that different regions within the same logical volume may reside on different physical media from the rest of the logical volume.This could be used by a journalized file system to automatically place the file system log portion of the logical volume on different media from the rest of the file system. This allows the file system isolate log writes for performance reasons from the file system data. This allows the administrator to put the log portion of the file system on a device with a fast write cache thus increasing performance of file system operations requiring meta data updates.

We also propose automatic allocations between two or more logical volumes such that logical volumes allocations are kept on separate media. An allocation rule would be defined for each logical volume listing other logical volumes that can't share allo...