Dell Perc 5/i Performance issues

Garrett Cooper yanefbsd at
Sat Jun 19 11:17:21 UTC 2010

On Sat, Jun 19, 2010 at 2:58 AM, oizs <oizs at> wrote:
> I tried almost everything raid 0 1 5 10 with all kind of stripes 32/64/128
> and settings direct io/cached/read-ahead/wt/wb/disk-cache but nothing seems
> to work.
> I changed the card to another dell perc 5 which had an older firmware. Tried
> 4 kind of motherboards even tried changing the os to linux and windows xp/7.
> In windows I got some funny results 1.3MB/s with write-back and 150MB/s
> reads with 5 disks in raid0.
> I just wanted to have a hw raid with no problems since the motherboard
> 88sx7042 and bsd did not like eachother.
> On 2010.06.19. 11:07, Svein Skogen (Listmail Account) wrote:
>> 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.
>>> ( 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)

Dumb question: are you sure that the problem that you're seeing isn't
in fact inhibited by the application that you're getting `performance'
results with?

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