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@xxxxxxxxxxxxx http://www.gregsmith.com
Baltimore, MD
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