From: Dave Chinner <david@fromorbit.com>
To: Stefan Ring <stefanrin@gmail.com>
Cc: Linux fs XFS <xfs@oss.sgi.com>
Subject: Re: A little RAID experiment
Date: Thu, 11 Oct 2012 08:27:33 +1100 [thread overview]
Message-ID: <20121010212733.GW23644@dastard> (raw)
In-Reply-To: <CAAxjCEwYyzTLTJk7SU0t=1SnT-V=7VadtKd0v9qj0soXtJ8XTg@mail.gmail.com>
On Wed, Oct 10, 2012 at 04:57:47PM +0200, Stefan Ring wrote:
> Btw, one of our customers recently aquired new gear with HP SmartArray
> Gen8 controllers. Now they are something to get excited about! This is
> the kind of write performance I would expect from an expensive server
> product. Check this out (this is again my artificial benchmark as well
> as random write of 4K blocks):
>
> SmartArray P400, 6 300G disks (10k, SAS) RAID 6, 256M BBWC:
^^^^
.....
> SmartArray Gen8, 8 300G disks (15k, SAS) RAID 5, 2GB FBWC:
^^^^
That's the reason for the difference in performance...
> So yeah, the disks are a bit faster. But what does that matter when
> there is such a huge difference otherwise?
Just inidicates that the working set for your test is much more
resident in the controller cache - has nothing to do with the disk
speeds. Tun a larger set of files/workload and the results will end
up a lot closer to disk speed instead of cache speed...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2012-10-10 21:26 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-25 8:07 A little RAID experiment Stefan Ring
2012-04-25 14:17 ` Roger Willcocks
2012-04-25 16:23 ` Stefan Ring
2012-04-27 14:03 ` Stan Hoeppner
2012-04-26 8:53 ` Stefan Ring
2012-04-27 15:10 ` Stan Hoeppner
2012-04-27 15:28 ` Joe Landman
2012-04-28 4:42 ` Stan Hoeppner
2012-04-27 13:50 ` Stan Hoeppner
2012-05-01 10:46 ` Stefan Ring
2012-05-30 11:07 ` Stefan Ring
2012-05-31 1:30 ` Stan Hoeppner
2012-05-31 6:44 ` Stefan Ring
2012-07-16 19:57 ` Stefan Ring
2012-07-16 20:03 ` Stefan Ring
2012-07-16 20:05 ` Stefan Ring
2012-07-16 21:27 ` Stan Hoeppner
2012-07-16 21:58 ` Stefan Ring
2012-07-17 1:39 ` Stan Hoeppner
2012-07-17 5:26 ` Dave Chinner
2012-07-18 2:18 ` Stan Hoeppner
2012-07-18 6:44 ` Stefan Ring
2012-07-18 7:09 ` Stan Hoeppner
2012-07-18 7:22 ` Stefan Ring
2012-07-18 10:24 ` Stan Hoeppner
2012-07-18 12:32 ` Stefan Ring
2012-07-18 12:37 ` Stefan Ring
2012-07-19 3:08 ` Stan Hoeppner
2012-07-25 9:29 ` Stefan Ring
2012-07-25 10:00 ` Stan Hoeppner
2012-07-25 10:08 ` Stefan Ring
2012-07-25 11:00 ` Stan Hoeppner
2012-07-26 8:32 ` Dave Chinner
2012-09-11 16:37 ` Stefan Ring
2012-07-16 22:16 ` Stefan Ring
2012-10-10 14:57 ` Stefan Ring
2012-10-10 21:27 ` Dave Chinner [this message]
2012-10-10 22:01 ` Stefan Ring
-- strict thread matches above, loose matches on Subject: below --
2012-04-26 22:33 Richard Scobie
2012-04-27 21:30 ` Emmanuel Florac
2012-04-28 4:15 ` Richard Scobie
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