Re: Advice on RAID card - Mailing list pgsql-performance

From Joshua D. Drake
Subject Re: Advice on RAID card
Date
Msg-id 4336CEAA.7070208@commandprompt.com
Whole thread Raw
In response to Re: Advice on RAID card  (PFC <lists@boutiquenumerique.com>)
Responses Re: Advice on RAID card
List pgsql-performance
>
>     Even for RAID5 ? it uses a bit more CPU for the parity calculations.

I honestly can't speak to RAID 5. I don't (and won't) use it. RAID 5 is
a little brutal when under
heavy write load. I use either 1, or 10.

>     An advantage of software raid, is that if the RAID card dies, you
> have to  buy the same one ; whether I think that you can transfer a
> bunch of  software RAID5 disks to another machine if the machine
> they're in dies...

There is a huge advantage to software raid on all kinds of levels. If
you have the CPU then I suggest
it. However you will never get the performance out of software raid on
the high level (think 1 gig of cache)
that you would on a software raid setup.

It is a bit of a tradeoff but for most installations software raid is
more than adequate.

Sincerely,

Joshua D. Drake




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