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Date:      Fri, 11 Jan 2013 00:39:07 +0800 (SGT)
From:      Patrick Dung <patrick_dkt@yahoo.com.hk>
To:        Artem Belevich <art@freebsd.org>
Cc:        freebsd-fs <freebsd-fs@freebsd.org>
Subject:   Re: ZFS sub-optimal performance with default setting
Message-ID:  <1357835947.77658.YahooMailClassic@web190806.mail.sg3.yahoo.com>
In-Reply-To: <CAFqOu6gE2C1FoqZWVKKcw9=sKYagrwT5LpVo-jipbxTyLmjFVA@mail.gmail.com>

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Hi Artem,

Thanks for reply.

I have tried some tests, good and bad result is in below..........

logbias=3Dthroughput, primarycache=3Dall, sync=3Dstandard
Result: SQL
Key =A0=A0 =A0Value =A0=A0 =A0Time =A0=A0 =A0Comment
Insert Time: =A0=A0 =A010000 =A0=A0 =A028 s :-( =A0=A0 =A0Should not take m=
ore than 5's on an average system.
Update Time: =A0=A0 =A010000 =A0=A0 =A029 s :-( =A0=A0 =A0Should not take m=
ore than 9's on an average system.
Select Time: =A0=A0 =A010000 =A0=A0 =A08 s :-( =A0=A0 =A0Should not take mo=
re than 6's on an average system.
Delete Time: =A0=A0 =A010000 =A0=A0 =A024 s :-( =A0=A0 =A0Should not take m=
ore than 5's on an average system.=20

logbias=3Dlatency, primarycache=3Dall, sync=3Dstandard
Result: SQL
Key =A0=A0 =A0Value =A0=A0 =A0Time =A0=A0 =A0Comment
Insert Time: =A0=A0 =A010000 =A0=A0 =A09 s :-( =A0=A0 =A0Should not take mo=
re than 5's on an average system.
Update Time: =A0=A0 =A010000 =A0=A0 =A010 s :-( =A0=A0 =A0Should not take m=
ore than 9's on an average system.
Select Time: =A0=A0 =A010000 =A0=A0 =A04 s :-) =A0=A0 =A0Looks fine!
Delete Time: =A0=A0 =A010000 =A0=A0 =A08 s :-( =A0=A0 =A0Should not take mo=
re than 5's on an average system.=20

logbias=3Dlatency, primarycache=3Dall, sync=3Ddisabled
Result: SQL
Key =A0=A0 =A0Value =A0=A0 =A0Time =A0=A0 =A0Comment
Insert Time: =A0=A0 =A010000 =A0=A0 =A03 s :-) =A0=A0 =A0Looks fine!
Update Time: =A0=A0 =A010000 =A0=A0 =A03 s :-) =A0=A0 =A0Looks fine!
Select Time: =A0=A0 =A010000 =A0=A0 =A03 s :-) =A0=A0 =A0Looks fine!
Delete Time: =A0=A0 =A010000 =A0=A0 =A03 s :-) =A0=A0 =A0Looks fine!=20
Regards,
Patrick

--- On Thu, 1/10/13, Artem Belevich <art@freebsd.org> wrote:

From: Artem Belevich <art@freebsd.org>
Subject: Re: ZFS sub-optimal performance with default setting
To: "Patrick Dung" <patrick_dkt@yahoo.com.hk>
Cc: "freebsd-fs" <freebsd-fs@freebsd.org>
Date: Thursday, January 10, 2013, 9:37 AM

On Wed, Jan 9, 2013 at 6:31 AM, Patrick Dung <patrick_dkt@yahoo.com.hk> wro=
te:
> Hi freebsd-fs!
>
> I have my the original question in:
> http://archives.postgresql.org/pgsql-performance/2013-01/msg00044.php
> But later it was found out the bottleneck seems to be the ZFS with out a =
fast ZIL.
> Please give some advise, thanks.

For database storage on ZFS it may be necessary to change ZFS record
size to match database page size. At least that's what one of the
things Oracle recommends for oracle database:
http://www.oracle.com/technetwork/server-storage/solaris10/config-solaris-z=
fs-wp-167894.pdf

You may also check if disabling prefetching (via
vfs.zfs.prefetch_disable=3D1 tunable in loader.conf) helps your
workload.

--Artem



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