Scott Marlowe schrieb:
> On Wed, Dec 10, 2008 at 12:45 AM, Mario Weilguni <mweilguni@sime.com> wrote:
>
>> A customer of us uses the P400 on a different machine, 8 SAS drives (Raid 5
>> as well), and the performance is very, very good. So we thought it's a good
>> choice. Maybe the SATA drives are the root of this problem?
>>
>
> What tests have you or the customer done to confirm that performance
> is very very good? A lot of times the system is not as fast as the
> customer thinks, it's just faster than it was before and they're
> happy. Also, there could be problems in the driver or firmware on
> your P400 versus the customer one. I'd look for those differences as
> well. I doubt SATA versus SAS is the problem, but who knows...
>
>
Well, I cannot take the box offline to make usefull tests like tiobench
or bonnie, but even with the current service running I get from a simple
dd between 270 and 340 MB/sec sustained read over 30% of the disk.
It also performed extremly good when I put the box into production,
pg_bench values were impressing, but I do not have them at hand.
However, currently we are seriously considering dropping RAID5 in favor
of RAID10, we will test this week if this performs better.
Regards
Mario