Re: Which RAID Controllers to pick/avoid?

Dan Birken wrote:
> ADAPTEC 3405 RAID Controller
> ADAPTEC 4800 RAID Controller

The 3405 and 4800 are two of Adaptec's older cards with only 128MB of
cache on them. Those are on the slow side compared to the others listed.

> LSI MegaRaid 8308 RAID Controller
> ADAPTEC 5405 RAID Controller
> ADAPTEC 5405Z RAID Controller
> ADAPTEC 5805 RAID Controller
> ADAPTEC 5805Z RAID Controller

The LSI cards are some of the most popular and known to work well with
PostgreSQL ones around.

I've recently tested a system based on the 5405, and as much as I've
hated Adaptec controllers in the past I have to admit this latest line
from them is pretty solid. My own benchmarks and the others I've seen
suggest it's easily capable of keeping up with the LSI and Areca
controllers Adaptec used to be seriously outrun by. See
http://www.tomshardware.com/reviews/adaptec-serial-controllers,1806-14.html
for example.

The "Z" variations use their "Zero-Maintenance Cache" instead of a
standard battery-backup unit; that's a small amount of flash memory and
a supercap, similar to the good caches on SSD:
http://www.adaptec.com/NR/rdonlyres/7FD8C372-8231-4727-B12B-5ABF79D9325C/0/6514_Series5Z_1_7.pdf

5405 has 256MB of cache, the others 512MB.

The 5405 and 5805 models do have a known problem where they overheat if
you don't have enough cooling in the server box, with the 5805 seeming
to be the bigger source of such issues. See the reviews at
http://www.newegg.com/Product/Product.aspx?Item=N82E16816103099 for
example. Scott Marlowe was griping recently about a similar issue in
some of the LSI models, too. I suspect it's a problem impacting several
of the larger RAID cards that use the big Intel IOP processors for their
RAID computations, given that's the part with the heatsink on it.

Quick summary: avoid the Adaptec 3405 and 4800. Rest are decent
cards. Just make sure you monitor the temperatures in your case (and
the card too if arcconf lets you, I haven't checked for that yet) if you
end up with a 5405/5805.

--
Greg Smith 2ndQuadrant US greg(at)2ndQuadrant(dot)com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books