Performance issues with 8.0 ZFS and sendfile/lighttpd
mloftis at wgops.com
Fri Nov 6 21:11:53 UTC 2009
--On Friday, November 06, 2009 3:31 PM -0500 Ben Kelly <ben at wanderview.com>
> Have you tried adjusting vfs.zfs.arc_meta_limit? I've noticed the
> default value for this is set poorly when the overall ARC size is small.
> This happens because various structure's not actually allocated from the
> ARC like dnodes and dbufs are included in the metadata usage stats. When
> the ARC is large this is somewhat negligible, but for small ARCs it
> overwhelms the calculated default metadata limit and you end up not
> caching any real file system metadata.
> You could try increasing the metadata limit or even better increase your
> maximum ARC size to something over 1GB. (I seem to remember your ARC
> size is 128M from earlier in the thread).
Nope, that was someone else, not setting any ARC limits (or any ZFS
settings at all actually).
> Hope that helps.
> - Ben
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