Dell Perc 5/i Performance issues

[Svein Skogen (Listmail Account)]

On 18.06.2010 01:50, oizs wrote:
> Hi,
> 
> I've bought a Dell Perc 5/i because I couldn't make the onboard marvell
> 88sx7042 work with 8.0/8.1 or current, but as lucky as I am, the best I
> can do with 4x1.5tb samsung in raid5 is 60MB/s writes and 90MB/s reads,
> with bbu/write-back/adaptive-read-ahead.
> 
> I was expecting at least twice of that, and I'm not sure what can I do
> to get that speed. (I've read man 7 tuning with no success)
> 
> As far as I know this controller should be as fast as on other systems.
> (Freebsd.org mx1 has one of these cards.)
> 
> I'm hoping somebody on the list reads this and helps because I can't
> afford to buy another card.

I've lost track of what actual boards Dell has OEMized to make the
various PERCs, but if I remember somewhat correctly, the PERC5 is
basically an LSI Megaraid SAS 8308elp with different labels and firmware?

If so, I've got that exact controller (minus the dell labels and
firmware) in my primary storage box here, and yes, you SHOULD be able to
get more performance out of it. What's your strip sizes and logical disk
layout?

(I've got the same board running on 8x 1T5 Seagates in RAID5+0, and that
setup easily pulls 5 times the values you're seeing, and by all logic
you should see about half of what I'm seeing)

//Svein

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