Dell Perc 5/i Performance issues

oizs oizs at
Sat Jun 19 09:58:57 UTC 2010

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)
> //Svein

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