RHEL3 and SAS5/iR: very bad performance

John Hodrien johnh at comp.leeds.ac.uk
Wed Jan 24 09:17:11 CST 2007


On Wed, 24 Jan 2007, Eric Rostetter wrote:

> Quoting Giulio Orsero <giulioo at gmail.com>:
>
>> Case #1 (simple SATA disk):
>> - bonnie (file=RAMx2): about 70MB/s writes, about 80MB/s reads
>> Case #2 (SAS5/iR DRV 2.06.32 FW-00.06.50.00-IE BIOS-6.06.00.02):
>> - bonnie (file=RAMx2): about 40MB/s writes, about 120MB/s reads
>
> This isn't bad.  RAID-1 will have slower writes (since it has to
> write twice), but faster reads (since it can do two reads at once)
> which is what you are seeing.
>
> So the performance of the disk setups seems fine as far as the
> bonnie test shows.

Should the RAID1 performance be much worse?  With large files shouldn't you
be disk throughput (not interface) limited, and so in the best case have
identical performance?

jh

-- 
"The great question that has never been answered, and which I have not yet
  been able to answer, despite my thirty years of research into the feminine
  soul, is 'What does a woman want?'."                -- Sigmund Freud



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