On Fri, Dec 17, 2010 at 10:32 AM, Craig James
<craig_james@emolecules.com> wrote:
> RAID5 is a Really Bad Idea for any database. It is S...L...O...W. It does
> NOT give better redundancy and security; RAID 10 with a battery-backed RAID
> controller card is massively better for performance and just as good for
> redundancy and security.
The real performance problem with RAID 5 won't show up until a drive
dies and it starts rebuilding, at which point it's then WAYYYY slower,
and while it's rebuilding you don't have redundancy. If you HAVE to
use stripes with redundancy, use RAID-6. It's no faster when working
right, but with a single dead drive it's still ok on performance and
can rebuild at leisure since there's till redundancy in the system.
But really if you're running a db on anything other than RAID-10 you
need to reassess your priorities.