Re: RAID card recommendation

Scott Carey wrote:

On 11/24/09 11:13 AM, "Scott Marlowe" <scott.marlowe@gmail.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