ZFSv28+NFSv4 poor file creation performance,
"sync=disabled" has no effect
gull at gull.us
Wed Aug 31 21:45:46 UTC 2011
I'm testing FreeBSD 9.0-BETA with an eye toward eventually using
FreeBSD 9.0 to replace some existing OpenSolaris 2008.11
installations. I've found NFS file creation performance (as measured
by Bonnie++) is equally slow for both with default settings. However,
on OpenSolaris I disable the ZIL to improve file creation performance.
This tuning parameter was removed from FreeBSD 9.0; its replacement
is supposed to be the per-filesystem flag "sync", but setting this
flag seems to have no effect.
I did recompile the FreeBSD kernel without debugging features before
doing the tests, so I don't think this is a case of debugging code
slowing things down.
Here's the relevant data; these are all from bonnie++'s "sequential
OpenSolaris 2008.11, default settings: 58/second
OpenSolaris 2008.11, with "zil_disable=1": 1258/second
FreeBSD 9.0-BETA, default settings: 107/second
FreeBSD 9.0-BETA, with "sync=disabled": 106/second
It appears the "sync" ZFS parameter has no effect in FreeBSD. Has
anyone else seen this? Is there a way to improve NFS file creation
performance now that zil_disable has been removed?
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