Dell Perc 5/i Performance issues

[krad]

On 18 June 2010 10:08, oizs <oizs at freemail.hu> wrote:

> I've seen people with the same configuration doing 160MB/s writes and
> 250MB/s+ reads with raid5 so I still think something isn't right. And using
> raid10 with 4 disks is a rather large waste of capacity.
>
> -zsozso
>
>
> On 2010.06.18. 1:55, Chuck Swiger wrote:
>
>> On Jun 17, 2010, at 4:50 PM, oizs wrote:
>>
>>
>>> 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)
>>>
>>>
>> Switch to using RAID-10 rather than RAID-5.  It's normal for RAID-5 to
>> have worse write performance than that of a single drive.
>>
>> Regards,
>>
>>
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what are your drives though? Are they SATA green/eco type drives or proper
SAS enterprise ones