[CentOS] 3Ware 9650SE tuning advice

Ray Van Dolson rayvd at bludgeon.org
Thu Jan 15 22:56:16 UTC 2009


Hello fellow sysadmins!

I've assembled a whitebox system with a SuperMicro motherboard, case,
8GB of memory and a single quad core Xeon processor.

I have two 9650SE-8LPML cards (8 ports each) in each server with 12 1TB
SATA drives total.  Three drives per "lane" on each card.

CentOS 5.2 x86_64.

I'm looking for advice on tuning this thing for performance.
Especially for the role of performing as either an NFS datastore for
VMware or an iSCSI one.

I set up two volumes (one for each card); one RAID6 and one RAID5.  I
used the default 64K block size and am trying various filesystems in
tandem with it.  I stumbled across the following recommendations on
3Ware's site:

  echo "64" > /sys/block/sda/queue/max_sectors_kb
  blockdev --setra 16384 /dev/sda
  echo "512" > /sys/block/sda/queue/nr_requests

But am wondering if there are other things I should be looking at,
including changing the IO scheduler.  Any particular options I should
use with filesystem creation to match up with my RAID block size?

I also noted that there is a newer 3Ware driver (2.26.08.004) available
than the one that comes stock with CentOS 5.2 (2.26.02.008).  Not sure
if I can expect performance improvement by "upgrading", and I imagine
I'd have to mess with my initrd file in any case or boot with a driver
disk option and blacklist the built-in driver...

Thanks for any feedback!

Ray


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