On Mon, Oct 01, 2007 at 12:57:05PM +0100, Robert Milkowski wrote: > Hello Neil, > > Thursday, September 27, 2007, 11:40:42 PM, you wrote: > > > NP> Roch - PAE wrote: > >> Pawel Jakub Dawidek writes: > >> > I'm CCing zfs-discuss@opensolaris.org, as this doesn't look like > >> > FreeBSD-specific problem. > >> > > >> > It looks there is a problem with block allocation(?) when we are near > >> > quota limit. tank/foo dataset has quota set to 10m: > >> > > >> > Without quota: > >> > > >> > FreeBSD: > >> > # dd if=/dev/zero of=/tank/test bs=512 count=20480 > >> > time: 0.7s > >> > > >> > Solaris: > >> > # dd if=/dev/zero of=/tank/test bs=512 count=20480 > >> > time: 4.5s > >> > > >> > With quota: > >> > > >> > FreeBSD: > >> > # dd if=/dev/zero of=/tank/foo/test bs=512 count=20480 > >> > dd: /tank/foo/test: Disc quota exceeded > >> > time: 306.5s > >> > > >> > Solaris: > >> > # dd if=/dev/zero of=/tank/foo/test bs=512 count=20480 > >> > write: Disc quota exceeded > >> > time: 602.7s > >> > > >> > CPU is almost entirely idle, but disk activity seems to be high. > >> > > >> > >> > >> Yes, as we are near quota limit, each transaction group > >> will accept a small amount as to not overshoot the limit. > >> > >> I don't know if we have the optimal strategy yet. > >> > >> -r > > NP> Aside from the quota perf issue, has any analysis been done as to > NP> why FreeBSD is over 6X faster than Solaris without quotas? > NP> Do other perf tests show a similar disparity? > NP> Is there a difference in dd itself? > NP> I assume that it was identical hardware and pool config.
(I don't see this e-mail in my ZFS inbox, that's why I'm replaying to Robert's e-mail.) Just to clarify. This was entirely different hardware. My e-mail was __only__ about quota performance in ZFS. Please, do not try to use those results for any other purpose. -- Pawel Jakub Dawidek http://www.wheel.pl [EMAIL PROTECTED] http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am!
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