CERC Performance Question

[ross levins]

To remove any issues with NFS and/or network why dont' you just try your 
test by writing/reading locally for read and write test
dd if=/dev/zero of=big_file bs=1024 count=5120000
dd of=/dev/zero if=big_file bs=1024 count=5120000

I have seen read/writes upto 80 to 90MB/second with this controller which 
also is too slow and in general this controller performs poorly.
thanks

>From: "Sturgis, Grant" <Grant.Sturgis at arraybiopharma.com>
>To: linux-poweredge at dell.com
>Subject: Re: CERC Performance Question
>Date: Tue, 25 Jul 2006 08:41:37 -0600>
>Can anyone comment if these numbers look normal or not?
>
>Thanks.
>
>Sturgis, Grant wrote:
> > Greetings List,
> >
> > I am experiencing very poor performance with a CERC SATA 1.5/6ch RAID
> > card wtih firmware v4.1-0.  Four disks are configured in RAID 5 and the
> > OS is RHEL ES 4.0.  I understand that this is not a high performance
> > RAID card or RAID configuration (write penalty associated with RAID 5),
> > but this just seems ridiculous.
> >
> > Created a 5GB file with the command:
> >
> > dd if=/dev/zero of=big_file bs=1024 count=5120000
> >
> > and then timed a move operation from an NFS mount to the local RAID
> > array connected at 1000Mbps end-to-end:
> >
> > time mv /hosts/server/test/big_file local_test_folder
> >
> > and the results were:
> >
> > 0.623u 34.342s 9:44.65 5.9%     0+0k 0+0io 3pf+0w
> >
> > This is over 10 minutes to move that much data over a gigabit
> > connection.  What's even worse is that the load average on the system
> > exceeded 18 resulting in an unusable system for all other users.  There
> > was no response to any commands or login attempts.
> >
> > Does this seem reasonable to you?  What can I do to improve this
> > performance (short of doing away with RAID 5)?
> >
> > Any comments and suggestions are very much appreciated.
> >
> > Thanks,
> >
> > Grant
> > ----------------
> >
> >
> >
> >
> > Pardon this rubbish:
> >
>
>
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