Date: Fri, 2 Sep 2011 09:29:33 -0700 From: David Brodbeck <brodbd@uw.edu> To: freebsd-fs@freebsd.org Subject: ZFSv28+NFSv4 poor file creation performance, "sync=disabled" has no effect Message-ID: <CAHHaOuY=BEMrhYuzXtD5AtXG7niLXEO1yhO5P4EimcsLuTrLXw@mail.gmail.com>
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I originally posted this on FreeBSD-questions, but it was suggested that I bring it here. 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 create" benchmark. The NFS client was RedHat Enterprise Linux 5.6. 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 So 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? -- David Brodbeck System Administrator, Linguistics University of Washington
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