Dell Perc 5/i Performance issues

Scott Long scottl at
Sun Jun 20 02:56:21 UTC 2010

On Jun 19, 2010, at 5:32 AM, Garrett Cooper wrote:
> On Sat, Jun 19, 2010 at 4:24 AM, Garrett Cooper <yanefbsd at> wrote:
>> 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.
> Furthermore, if the performance applications and your use scenarios
> are centered around reading, as opposed to writing, there is an option
> within mficontrol and the mfi(4) interface where you can actually
> enable read-ahead, instead of writeback (you unfortunately can't
> enable both scenarios). I realize that this is an artificial
> improvement in a way, but you should judge whether or not your
> application will be doing more reading than writing in whatever
> capacity it's doing...
> HTH,

No, that doesn't help.  I wrote the driver, and I have no flipping clue what you're talking about.


More information about the freebsd-current mailing list