CERC RAID5 performance lower than everyone else

[John Hodrien]

On Fri, 18 Jul 2008, Adam Nielsen wrote:

> Hi all,
>
> When researching the poor performance on the CERC SATA controller in a
> PE1800 here, I noticed that many people complain that they can't get
> speeds faster than ~40MB/sec read/write.
>
> What I'd like to know is how on earth people are getting speeds that
> high!  We've got five 160GB disks in RAID5, and I've yet to see read or
> write speed go above 7MB/sec.
>
> This is painfully slow, and while we've managed to crawl along for a
> while now it's really beginning to show.  Unfortunately it's still at
> least a year away before we can justify replacing the machine, so if
> anyone is able to offer any pointers as to how we can speed up the CERC
> in the meantime they'd be much appreciated!

Sounds reasonable to me.  I gave up on RAID 5 and switched to RAID 1.  When
the performance of that sucked I then dropped to software RAID 1.  That's got
it up to a stunning 25Mbyte/sec write speed.

The card is awful.

jh

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