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IOZone
So after testing the memory performance of our clusters using Linpack, View Results, what about the file system access performance? There are many variables at play in this area, so a higher-level view is appropriate rather than a too detailed view.
In order to have comparative numbers, I choose the package IOZone which seemed to be used for this type of activities. IOZone performs many different tests including read, re-read, write, re-write, read-and-write, random mix, backwards reads and a few others. The whole mix then might be an appropriate comparative standard. As details spin out, we could focus on those that most reflecct our environment best; probably random mix.
Setup
IOZone was compiled for x86 64 bit Linux and staged in a tarball. That tarball would be copied to the disk housing the file system in question, unpacked, and with the vanilla out of the box “rule set” invoked with './iozone -a -g 12G > output.out'. Then the results were saved and graphed. The reason for 12GB as the file size limit to test at the upper bounds was set because cluster greeentail memory footprint across the board is that. I did not raise the file size limit above the memory footprint to avoid introducing another variable. You can read all about it External Link
As some of the tests IOZOne performs put quite the load on the host (observed a single invocation to generate a load of 6), I ran IOZone with the LSF/Lava scheduler flag '-x' meaning exclusive use so no other programs would interfere.
