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Re: poor io performance with xfs+raid5

To: Mike Eldridge <diz@xxxxxxxxx>
Subject: Re: poor io performance with xfs+raid5
From: Austin Gonyou <austin@xxxxxxxxxxxxxxx>
Date: 25 Apr 2002 16:36:10 -0500
Cc: Steve Lord <lord@xxxxxxx>, linux-xfs@xxxxxxxxxxx
In-reply-to: <20020425160852.C14120@xxxxxxxxxxxxxxxx>
References: <20020425160852.C14120@xxxxxxxxxxxxxxxx>
Sender: owner-linux-xfs@xxxxxxxxxxx
Yeah..sorry I noticed it after reading again. :( 

On Thu, 2002-04-25 at 16:08, Mike Eldridge wrote:
> i feel like a broken record.  :)
> 
> it's an escalade 7850 ata raid card.
> 
> -mike
> 
> On Thu, Apr 25, 2002 at 03:45:23PM -0500, Austin Gonyou wrote:
> > What card is it, BTW?
> > 
> > 
> > On Thu, 2002-04-25 at 15:41, Mike Eldridge wrote:
> > > On Thu, Apr 25, 2002 at 03:19:05PM -0500, Steve Lord wrote:
> > > > Well, Duh! I should have seen that first time around, I get into
> the
> > > > habit of reading my email too fast!
> > > > 
> > > > We may be able to fix some things, if we can remake the
> filesystem.
> > > > First you need to know the stripe unit of your raid - we can feed
> > > > this into XFS to make it do stripe aligned allocations. This has
> > > > to be done by hand on linux. Take a look at the mkfs.xfs man page
> > > > and the section on sunit and swidth options. Probably bump your
> log
> > > size
> > > > up from the default somewhat, not sure how it ended up as 1839
> > > > that is scary.
> > > 
> > > RAID5 on this card offers only a 64K stripe size.  however, i will
> be
> > > recreating the array as RAID1 or RAID10, which offers stripe sizes
> from
> > > 64K to 1MB.  i'm not sure which is the best way to go.  i think that
> the
> > > best thing to do, considering additonal space requirements might be
> > > neccessary, is to go with multiple RAID1 arrays and let LVM do the
> > > striping.  any caveats here?
> > > 
> > > this particular box is a mail server and it handles a lot of i/o
> with
> > > pretty small files (< 64K).  i want to optimize for performance.
> > > unfortunately, this is also my *first* foray into xfs/lvm/raid, so i
> > > want to make sure i have as much information as possible before i
> carve
> > > it all in stone.
> > > 
> > > i need to go read some more about LVM...
> > > 
> > > as for the log, yeah, just over 7MB, i have no idea either.  info i
> have
> > > read suggests a 32MB log, but i'd like to use something bigger,
> perhaps
> > > 128MB.  any caveats to using a log of this size?
> > > 
> > > > You still have not said which kernel version you are running
> beyond
> > > 2.4,
> > > > unless I speed read over that too.
> > > 
> > > i did in a previous email.  :)
> > > 
> > > it's vanilla 2.4.18 with the xfs-1.1 release patches applied.
> > > 
> > > -mike
> > > 
> > >
> ------------------------------------------------------------------------
> > > --
> > >    /~\  the ascii                       all that is gold does not
> > > glitter
> > >    \ /  ribbon campaign                 not all those who wander are
> > > lost
> > >     X   against html                          -- jrr tolkien
> > >    / \  email!
> > > 
> > >           radiusd+mysql: http://www.cafes.net/~diz/kiss-radiusd
> > > 
> > >
> ------------------------------------------------------------------------
> > > --
> > -- 
> > Austin Gonyou
> > Systems Architect, CCNA
> > Coremetrics, Inc.
> > Phone: 512-698-7250
> > email: austin@xxxxxxxxxxxxxxx
> > 
> > "It is the part of a good shepherd to shear his flock, not to skin
> it."
> > Latin Proverb
> 
> 
> 
> 
> ------------------------------------------------------------------------
> --
>    /~\  the ascii                       all that is gold does not
> glitter
>    \ /  ribbon campaign                 not all those who wander are
> lost
>     X   against html                          -- jrr tolkien
>    / \  email!
> 
>           radiusd+mysql: http://www.cafes.net/~diz/kiss-radiusd
> 
> ------------------------------------------------------------------------
> --
-- 
Austin Gonyou
Systems Architect, CCNA
Coremetrics, Inc.
Phone: 512-698-7250
email: austin@xxxxxxxxxxxxxxx

"It is the part of a good shepherd to shear his flock, not to skin it."
Latin Proverb

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