[plug] SAN Advice

Nick Bannon nick at ucc.gu.uwa.edu.au
Fri Nov 16 13:00:50 WST 2007

On Fri, Nov 16, 2007 at 11:21:33AM +0900, Adrian Woodley wrote:
> I have to disagree with you here - FC will _always_ beat NFS for speed. 

We-ell... No, NAS _can_ beat FC. It would depend entirely on your
workload, but when I benchmarked Oracle and a custom database-y
applications on expensive NetApp NAS versus expensive EMC and Hitachi
SANs, the NetApp won... and it proved that the disc storage really wasn't
our main bottleneck anyway.

> And iSCSI isn't even worth considering.

iSCSI is a big fat stack of layers, yeah, though there's a surfeit of
thinner layers which will do the same job - e.g. Coraid AoE and Linux NBD.

FC HBAs don't have _that_ much to accelerate, they look much like
any other SCSI card. The sort of things that hardware acceleration
accelerates are often the sort of things that gigahertz CPUs are already
quite good at. It can help, but you need to prove that the thing that
needs helping is your current bottleneck before it's worthwhile.

On Fri, Oct 26, 2007 at 09:05:55AM +0800, Mark Slatem wrote:
> Thanks for the advice and the link you provided. The inquirer url shows
> the exact device we have been quoted on, the given price includes 1 x
> 100GB and 6 x 750GB Seagate SATA Drives.

Well, we can see that there's room to improve the hardware performance
if you try it out and find that it's lacking. You can RAID-5 or RAID-6
those drives if you mainly want a big chunk of space. You can RAID-10
those drives if you need better write speed. You can replace them with
150GB 10000rpm Raptors if you need more IOs/second.


   Nick Bannon   | "I made this letter longer than usual because
nick-sig at rcpt.to | I lack the time to make it shorter." - Pascal

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