From: David Brown <david.brown@hesbynett.no>
To: linux-raid@vger.kernel.org
Subject: Using of RAID10,offset for faster writes
Date: Sat, 09 Apr 2011 14:03:21 +0200 [thread overview]
Message-ID: <inphu9$5kl$1@dough.gmane.org> (raw)
During a discussion about RAID in another context (a Linux newsgroup), I
began thinking about the speeds of the different RAID10 layouts for
different usages. RAID10,far is often the fastest choice for general
use - you get striped reads for large reads, and access times are good
because you can get the data from either disk. The disadvantage is that
writes involve a lot of extra head movement, as you need copies of the
data on two widely separated areas on the each disk. But for general
use, you read a lot more often than you write, so the tradeoff is worth it.
In the discussion we were looking particularly at swap space on RAID.
This is a usage that requires a lot of writing, especially small writes.
Using the RAID10,offset layout should give you most of the benefits of
RAID10,far when it comes to reading - you don't get quite as efficient
block reads for large reads, but you can still do a lot of striping in
the reads. And writes will involve far less head movement, and so
should complete faster.
Has anyone tried this, or done any benchmarking?
next reply other threads:[~2011-04-09 12:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-09 12:03 David Brown [this message]
2011-04-09 15:05 ` Using of RAID10,offset for faster writes Keld Jørn Simonsen
2011-04-10 9:50 ` David Brown
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