[CentOS] Performance problem with CentOS and XFS on EMC
mhull-richter at datallegro.com
Fri Mar 9 21:16:54 UTC 2007
Good point (use a good XFS), but it seems I misspoke myself:
Whether we use JFS or XFS, when the cache is enabled, we get less than
50% of the performance we see when we use direct i/o. Direct i/o is not
an option for general use, so we need to understand why cached i/o is so
We write huge files sequentially on the whole and as a rule in our app,
so that is probably a factor. We believe that our i/o overwhelms the
block level elevator algorithm, and that the cache flush algorithm isn't
particularly concerned with sequential i/o.
Can anyone shed some light on this?
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