From: Emmanuel Florac <eflorac@intellique.com>
To: John Bokma <contact@johnbokma.com>
Cc: xfs@oss.sgi.com
Subject: Re: 30 TB RAID6 + XFS slow write performance
Date: Tue, 19 Jul 2011 10:37:19 +0200 [thread overview]
Message-ID: <20110719103719.18c4773f@galadriel.home> (raw)
In-Reply-To: <4E24907F.6020903@johnbokma.com>
Le Mon, 18 Jul 2011 14:58:55 -0500 vous écriviez:
> card: MegaRAID SAS 9260-16i
> disks: 14x Barracuda® XT ST33000651AS 3TB (2 hot spares).
> RAID6
> ~ 30TB
>
This card doesn't activate the write cache without a BBU present. Be
sure you have a BBU or the performance will always be unbearably awful.
Then proceed like Eric suggested. Initialize your filesystem with the
right options : su= your RAID stripe size, sw= your RAID array data
members (for RAID 6, the total number minus 2), don't forget the useful
option -l lazy-count=1, and mount with nobarriers and inode64.
BTW apparently you're confusing hot spares and parity drives. A RAID-6
array has 2 parity drives; then it may have or not 1 or more hot spares
(generally one is enough). I suppose your array is actually a 12 data +
2 parity drives.
regards,
--
------------------------------------------------------------------------
Emmanuel Florac | Direction technique
| Intellique
| <eflorac@intellique.com>
| +33 1 78 94 84 02
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next prev parent reply other threads:[~2011-07-19 8:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-18 19:58 30 TB RAID6 + XFS slow write performance John Bokma
2011-07-19 0:00 ` Eric Sandeen
2011-07-19 8:37 ` Emmanuel Florac [this message]
2011-07-19 22:37 ` Stan Hoeppner
2011-07-20 0:20 ` Dave Chinner
2011-07-20 5:16 ` Stan Hoeppner
2011-07-20 6:44 ` Dave Chinner
2011-07-20 12:10 ` Stan Hoeppner
2011-07-20 14:04 ` Michael Monnerie
2011-07-20 23:01 ` Dave Chinner
2011-07-21 6:19 ` Michael Monnerie
2011-07-21 6:48 ` Dave Chinner
2011-07-22 6:10 ` Michael Monnerie
2011-07-22 18:05 ` Stan Hoeppner
2011-07-22 23:10 ` Dave Chinner
2011-07-24 6:14 ` Stan Hoeppner
2011-07-24 8:47 ` Michael Monnerie
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