Luke,
How did you measure 800MB/sec, is it cached, or physical I/O?
-anjan
-----Original Message-----
From: Luke Lonergan [mailto:LLonergan@greenplum.com]
Sent: Wednesday, December 14, 2005 2:10 AM
To: Charles Sprickman; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] SAN/NAS options
Charles,
> Lastly, one thing that I'm not yet finding in trying to
> educate myself on SANs is a good overview of what's come out
> in the past few years that's more affordable than the old
> big-iron stuff. For example I saw some brief info on this
> list's archives about the Dell/EMC offerings. Anything else
> in that vein to look at?
My two cents: SAN is a bad investment, go for big internal storage.
The 3Ware or Areca SATA RAID adapters kick butt and if you look in the
newest colos (I was just in ours "365main.net" today), you will see rack
on rack of machines with from 4 to 16 internal SATA drives. Are they
all DB servers? Not necessarily, but that's where things are headed.
You can get a 3U server with dual opteron 250s, 16GB RAM and 16x 400GB
SATAII drives with the 3Ware 9550SX controller for $10K - we just
ordered 4 of them. I don't think you can buy an external disk chassis
and a Fibre channel NIC for that.
Performance? 800MB/s RAID5 reads, 400MB/s RAID5 writes. Random IOs are
also very high for RAID10, but we don't use it so YMMV - look at Areca
and 3Ware.
Managability? Good web management interfaces with 6+ years of
development from 3Ware, e-mail, online rebuild options, all the goodies.
No "snapshot" or offline backup features like the high-end SANs, but do
you really need it?
Need more power or storage over time? Run a parallel DB like Bizgres
MPP, you can add more servers with internal storage and increase your
I/O, CPU and memory.
- Luke
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