Re: RAID card recommendation

Scott Carey wrote:
> On 11/24/09 11:13 AM, "Scott Marlowe" <scott(dot)marlowe(at)gmail(dot)com> wrote:
>
>
>
>> They get good reviews as well. Both manufacturers have their "star"
>> performers, and their "utility" or work group class controllers. For
>> what you're doing the areca 12xx or 3ware 95xx series should do fine.
>>
>
> -1 to 3ware's SATA solutions
>
> 3ware 95xx and 96xx had performance somewhere between PERC 5 (horrid) and
> PERC 6 (mediocre) when I tested them with large SATA drives with RAID 10.
> Haven't tried raid 6 or 5. Haven't tried the "SA" model that supports SAS.
> When a competing card (Areca or Adaptec) gets 3x the sequential throughput
> on an 8 disk RAID 10 and only catches up to be 60% the speed after heavy
> tuning of readahead value, there's something wrong.
> Random access throughput doesn't suffer like that however -- but its nice
> when the I/O can sequential scan faser than postgres can read the tuples.
>
What operating system?

I am running under FreeBSD with 96xx series and am getting EXCELLENT
performance. Under Postgres 8.4.x on identical hardware except for the
disk controller, I am pulling a literal 3x the iops on the same disks
that I do with the Adaptec (!)

I DID note that under Linux the same hardware was a slug.

Hmmmmm...

-- Karl