Date: Mon, 1 Oct 2007 12:57:05 +0100 From: Robert Milkowski <rmilkowski@task.gda.pl> To: Neil Perrin <Neil.Perrin@Sun.COM> Cc: freebsd-fs@freebsd.org, zfs-discuss@opensolaris.org, Roch - PAE <Roch.Bourbonnais@Sun.COM> Subject: Re[2]: [zfs-discuss] ZFS (and quota) Message-ID: <14950433.20071001125705@task.gda.pl> In-Reply-To: <46FC316A.8010004@Sun.COM> References: <BE54DA53-0353-4EB3-B232-6A7193522582@stromnet.se> <20070920115621.GF4517@garage.freebsd.pl> <8B5FB4B1-2398-491C-95F4-E79361606916@stromnet.se> <20070921142540.GB5690@garage.freebsd.pl> <18167.56892.707010.947405@gargle.gargle.HOWL> <46FC316A.8010004@Sun.COM>
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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.
Good question.
It should have been cached on Solaris so it should definitely be below
1s range.
--
Best regards,
Robert mailto:rmilkowski@task.gda.pl
http://milek.blogspot.com
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