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Message-ID: <c33e4330804232323p1b6d5121oc56b0c43663a4e84@mail.gmail.com>
Date: Thu, 24 Apr 2008 02:23:45 -0400
From: "Michael Darling" <darlingm@gmail.com>
To: "David Chinner" <dgc@sgi.com>, "Eric Sandeen" <sandeen@sandeen.net>,
        xfs@oss.sgi.com
Subject: Re: XFS drops create/delete files to 6.6% of EXT3 (software raid) and to 0.6% of EXT3 (3ware hardware raid)
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Eric, for the numbers you provided, are you using a single drive, software
raid, or hardware raid?  If a hardware raid, is it a 3ware card?

I hadn't seen the nobarrier mount option before.  Using that changes
sequential creates from about 190/second to about 2500/second, and changes
sequential deletes from about 170/second to about 3700/second.

I don't yet have a BBU for the 3ware card, but would certainly get one if we
go with the 3ware card before we start putting real data on the raid.  Am I
right that with a BBU unit and a battery backup for the server as a whole,
that nobarrier would be safe to use?

Not using nobarrier, but using logbsize 256k changes sequential creates from
about 190/second to about 270/second.  So, it's an improvement, but no where
near where a software raid performs (1600/second) or where the hardware raid
performs with nobarrier.


On Thu, Apr 24, 2008 at 1:33 AM, David Chinner <dgc@sgi.com> wrote:

> On Wed, Apr 23, 2008 at 11:01:51PM -0500, Eric Sandeen wrote:
> > Michael Darling wrote:
> > > I am preparing a new server, and benchmarking EXT3 against XFS, both
> using
> > > software RAID and hardware RAID using a 3ware 9650SE-4LPML.
> > >
> > > Using bonnie++ as a benchmark, I am seeing significant performance
> boosts in
> > > my block sequential reads and writes moving from EXT3 to XFS.  I am
> aware
> > > that XFS won't create and delete files as quickly as EXT3, however I
> am
> > > seeing drops from 29455/second to 1957/second using software RAID, and
> from
> > > 32524/second to 189/second using hardware RAID.  I'm not sure if when
> using
> > > software raid, if creating and deleting files should drop to 6.6% of
> EXT3.
> > > But, what I'm pretty sure of, is when using hardware raid, that
> creating and
> > > deleting files shouldn't drop to 0.6% of EXT3.
> >
> > So I played with this a little on 2.6.25, on plain partitions.
> >
> > I saw similar numbers; for example, sequential creates:
> >
> > ext3:         23698/s
> > xfs:            319/s
> > xfs,nobarrier:         4478/s
>
> And with logbsize=256k?
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> Principal Engineer
> SGI Australian Software Group
>


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