Dell Perc 5/i Performance issues

Garrett Cooper yanefbsd at
Sat Jun 19 11:24:49 UTC 2010

On Sat, Jun 19, 2010 at 4:21 AM, oizs <oizs at> wrote:
> Since I tested it on different kind of os's, and with at least 5 testing
> applications, I don't think that would be the case.
> On 2010.06.19. 13:17, Garrett Cooper wrote:
>> 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?

If your applications aren't well suited for your hardware's
capabilities, then of course performance will be bad.

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