From: Emmanuel Florac <eflorac@intellique.com>
To: Stan Hoeppner <stan@hardwarefreak.com>
Cc: xfs@oss.sgi.com
Subject: Re: RAID6 r-m-w, op-journaled fs, SSDs
Date: Sun, 1 May 2011 11:11:52 +0200 [thread overview]
Message-ID: <20110501111152.5913b9c5@galadriel2.home> (raw)
In-Reply-To: <4DBC68DA.1090708@hardwarefreak.com>
Le Sat, 30 Apr 2011 14:54:02 -0500 vous écriviez:
> Just having write back cache isn't magic by itself. The cache
> management algorithm and configuration thereof are often as
> important, if not more, than the total cache size on the RAID HBA or
> SAN controller.
>
> Poor cache management, I'd guess, is one reason why you see Areca
> RAID cards with 1-4GB cache DRAM whereas competing cards w/ similar
> price/performance/features from LSI, Adaptec, and others sport 512MB.
Yes, probably. To give some meat to the argument :
Using XFS mounted nobarrier on an 8 drives RAID-6 array with WB cache :
30000 journal (file creation/deletion) operations/s
Using XFS with barriers on the same RAID : 7000 journal operations/s
Using XFS nobarrier with WT cache : 700 journal op/s.
--
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Emmanuel Florac | Direction technique
| Intellique
| <eflorac@intellique.com>
| +33 1 78 94 84 02
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next prev parent reply other threads:[~2011-05-01 9:08 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-30 15:27 RAID6 r-m-w, op-journaled fs, SSDs Peter Grandi
2011-04-30 16:02 ` Emmanuel Florac
2011-04-30 19:54 ` Stan Hoeppner
2011-04-30 21:50 ` Michael Monnerie
2011-05-01 3:17 ` Stan Hoeppner
2011-05-01 9:14 ` Emmanuel Florac
2011-05-01 9:11 ` Emmanuel Florac [this message]
2011-04-30 22:27 ` NeilBrown
2011-05-01 15:31 ` Peter Grandi
2011-05-01 18:32 ` David Brown
2011-05-01 9:36 ` Dave Chinner
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