How to Use the Rebalance File System Utility

Solution ID: 43

Created: 7/31/2008

DETAILS:

How rebalance works:

During a rebalancing run on an IBRIX file system, files are moved from source

segments to destination segments. IBRIX Fusion calculates the average

aggregate utilization of all the source segments, then moves files from sources to

destinations to bring each candidate source segment as close as possible to the

calculated utilization threshold. The final absolute percent usage in the segments

depends on the average file size for the target file system.

If you do not specify any sources or destinations for a run, candidate segments

are sorted into sources and destinations and then rebalanced as evenly as

possible. If you specify sources, all other candidate segments in the file system

are tagged as destinations, and vice versa if you specify destinations. Following

the general rule, IBRIX Fusion will calculate the utilization threshold from the

sources and then bring the sources as close as possible to this value by evenly

distributing their excess files among all the destinations. If you specified sources,

the end result is that only those segments are rebalanced, and the overflow is

distributed among all remaining candidate segments.

If you specified destinations, the end result is that all segments except the

specified destinations are rebalanced, and the overflow is distributed only to the

destinations. If you specify both sources and destinations, only the specified

sources are rebalanced, and the overflow is distributed only among the specified

destinations. If there is not enough aggregate room in destination segments to

hold the files that must be moved from source segments in order to balance the

sources, IBRIX Fusion issues an error message and does not move any files.

The more restricted the number of destinations, the higher the likelihood of this

error.

Note: above excerpt referenced from Ibrix User's Guide Ch3.

General Rebalance job:

From the Fusion Manger execute

#/usr/local/ibrix/bin/ibrix_rebalance -r -f FS_NAME -c

-c = corrective rebalance without the -c no actual rebalancing is done.

Advanced Rebalance jobs:

From Ibrix 3.x or > the rebalance utility which carries the ability to conduct source

to target segment migrations can now also migrate files from Segments based

on file size criteria. Natively the rebalance algorithm will seek out any sized file[s]

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How to Use the Rebalance File System Utility Solution ID: 43 Created: 7/31/2008 DETAILS: How rebalance works: During a rebalancing run on an IBRIX file system, files are moved from source segments to destination segments. IBRIX Fusion calculates the average aggregate utilization of all the source segments, then moves files from sources to destinations to bring each candidate source segment as close as possible to the calculated utilization threshold.
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on specified source Segments and move them to the specified target Segments on a typical "source to target(destination)" rebalance job. So one can initiate a rebalance job to balance said source Segments by distributing the overflow of excess files across that of the specified target(destination) Segments and by calling the -O "-p all" option you are telling rebalance utiltiy to randomly migrate all sized files from source "-s" Segments to respective target(destination) "-d" Segments.
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