From: Johannes Segitz <johannes.segitz@gmail.com>
To: linux-raid@vger.kernel.org
Subject: Re: Performance of a software raid 5
Date: Tue, 21 Apr 2009 03:05:41 +0200 [thread overview]
Message-ID: <a5cd9eed0904201805n1b52aafm206bda5a1afc0b5c@mail.gmail.com> (raw)
In-Reply-To: <49ED18E6.1090301@anonymous.org.uk>
On Tue, Apr 21, 2009 at 2:52 AM, John Robinson
<john.robinson@anonymous.org.uk> wrote:
> There's no redundancy but it's still the RAID-5 4-disc layout with 3 data
> and 1 parity, the parity on a different disc in each stripe. In your case
> with a missing disc, for 3 stripes in 4 you have 2 data and 1 parity. Of
> course the parity is having to be calculated when you're writing, and
> whatever would be written to your missing disc is being discarded.
you're right, i didn't think of that. But calculating an xor isn't really
a big deal (especially with the aes on top of it) so i still can't see why
it's so slow
Johannes
next prev parent reply other threads:[~2009-04-21 1:05 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-20 17:12 Performance of a software raid 5 Johannes Segitz
2009-04-20 23:46 ` John Robinson
2009-04-21 0:10 ` Johannes Segitz
2009-04-21 0:52 ` John Robinson
2009-04-21 1:05 ` Johannes Segitz [this message]
2009-04-21 1:12 ` John Robinson
2009-04-21 1:19 ` NeilBrown
2009-04-21 2:04 ` Johannes Segitz
2009-04-21 5:46 ` Neil Brown
2009-04-21 12:40 ` Johannes Segitz
2009-04-24 13:49 ` Johannes Segitz
2009-04-26 17:03 ` Johannes Segitz
2009-04-21 18:56 ` Corey Hickey
2009-04-22 12:29 ` Bill Davidsen
2009-04-22 22:32 ` Corey Hickey
2009-04-22 9:07 ` Goswin von Brederlow
2009-04-21 0:44 ` Poor write performance with write-intent bitmap? John Robinson
2009-04-21 1:33 ` NeilBrown
2009-04-21 2:13 ` John Robinson
2009-04-21 5:50 ` Neil Brown
2009-04-21 12:05 ` John Robinson
2009-05-22 23:00 ` Redeeman
2009-04-22 9:16 ` Goswin von Brederlow
2009-04-22 12:41 ` John Robinson
2009-04-22 14:02 ` Goswin von Brederlow
2009-04-23 7:48 ` John Robinson
2009-04-22 14:21 ` Andre Noll
2009-04-23 8:04 ` John Robinson
2009-04-23 20:23 ` Goswin von Brederlow
2009-04-21 16:00 ` Bill Davidsen
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