Re: Filesystem benchmarking for pg 8.3.3 server

9 aug 2008 kl. 00.47 skrev Greg Smith:

> On Fri, 8 Aug 2008, Henrik wrote:
>
>> It feels like there is something fishy going on. Maybe the RAID 10
>> implementation on the PERC/6e is crap?
>
> Normally, when a SATA implementation is running significantly faster
> than a SAS one, it's because there's some write cache in the SATA
> disks turned on (which they usually are unless you go out of your
> way to disable them). Since all non-battery backed caches need to
> get turned off for reliable database use, you might want to double-
> check that on the controller that's driving the SATA disks.

Lucky for my I have BBU on all my controllers cards and I'm also not
using the SATA drives for database. That is why I bought the SAS
drives :) Just got confused when the SATA RAID 5 was sooo much faster
than the SAS RAID10, even random writes. But I should have realized
that SAS is only faster if the number of drives are equal :)

Thanks for the input!

Cheers,
Henke

>
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> * Greg Smith gsmith@gregsmith.com http://www.gregsmith.com
> Baltimore, MD
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