AIX Memory Cleanup

acubedec15
acubedec15 used Ask the Experts™
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I know that /usr/lib/perf/crush cleans up unused memory segments on an AIX server but what would be the performance implications for running this command.

Second question, If we run command in /usr/lib/perf or as a matter of fact any performance related commands like "vmstat", "iostat" etc, Will there be a performance hit..???
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Take a look at...

http://ibmsystemsmag.com/Blogs/AIXchange/Archive/what-is-crush-i/

/usr/lib/perf/crush <integer>

you calculate the integer using output from 'svmon -G' : memory size total - memory pinned = <integer>

Rumor has it that it was developed for internal IBM use to clean memory pages before running benchmark applications.

Your applications might slow down for a moment but you will see a much bigger free list afterwards.

Regarding the performance monitoring tools, if you run them once, no issue. Running then continuously obviously takes some resources, but if you note that the command itself does not appear on the output performance, it use is assumed to be insignificant.

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