Re: raid10 write performance

On Wed, Jun 23, 2010 at 6:06 AM, Ivan Voras <ivoras@freebsd.org> wrote:
> On 06/22/10 16:40, Greg Smith wrote:
>> Grzegorz Jaśkiewicz wrote:
>>> raid: serveRAID M5014 SAS/SATA controller
>>>
>>
>> Do the "performant servers" have a different RAID card?  This one has
>> terrible performance, and could alone be the source of your issue.  The
>> ServeRAID cards are slow in general, and certainly slow running RAID10.
>
> What are some good RAID10 cards nowadays?

LSI, Areca, 3Ware (now LSI I believe)

> On the other hand, RAID10 is simple enough that soft-RAID
> implementations should be more than adequate - any ideas why a dedicated
> card has it "slow"?

This is mostly a problem with some older cards that focused on RAID-5
performance, and RAID-10 was an afterthought.  On many of these cards
(older PERCs for instance) it was faster to either use a bunch of
RAID-1 pairs in hardware with RAID-0 in software on top, or put the
thing into JBOD mode and do it all in software.