Re: 10K vs 15k rpm for analytics

Francisco Reyes wrote:
> Who are you using for SAS?
> One thing I like about 3ware is their management utility works under
> both FreeBSD and Linux well.

3ware has turned into a division within LSI now, so I have my doubts
about their long-term viability as a separate product as well.

LSI used to be the reliable, open, but somewhat slower cards around, but
that doesn't seem to be the case with their SAS products anymore. I've
worked on two systems using their MegaRAID SAS 1078 chipset in RAID10
recently and been very impressed with both. That's what I'm
recommending to clients now too--especially people who liked Dell
anyway. (HP customers are still getting pointed toward their
P400/600/800. 3ware in white box systems, still OK, but only SATA.
Areca is fast, but they're really not taking the whole driver thing
seriously.)

You can get that direct from LSI as the MegaRAID SAS 8888ELP:
http://www.lsi.com/storage_home/products_home/internal_raid/megaraid_sas/megaraid_sas_8888elp/
as well as some similar models. And that's what Dell sells as their
PERC6. Here's what a typical one looks like from Linux's perspective,
just to confirm which card/chipset/driver I'm talking about:

# lspci -v
03:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 1078
(rev 04)
Subsystem: Dell PERC 6/i Integrated RAID Controller

$ /sbin/modinfo megaraid_sas
filename:
/lib/modules/2.6.18-164.el5/kernel/drivers/scsi/megaraid/megaraid_sas.ko
description: LSI MegaRAID SAS Driver
author: megaraidlinux(at)lsi(dot)com
version: 00.00.04.08-RH2
license: GPL

As for the management utility, LSI ships "MegaCli[64]" as a statically
linked Linux binary. Plenty of reports of people running it on FreeBSD
with no problems via Linux emulation libraries--it's a really basic CLI
tool and whatever interface it talks to card via seems to emulate just
fine. UI is awful, but once you find the magic cheat sheet at
http://tools.rapidsoft.de/perc/ it's not too bad. No direct SMART
monitoring here either, which is disappointing, but you can get some
pretty detailed data out of MegaCli so it's not terrible.

I've seen >100MB/s per drive on reads out of small RAID10 arrays, and
cleared 1GB/s on larger ones (all on RHEL5+ext3) with this controller on
recent installs.

--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg(at)2ndQuadrant(dot)com www.2ndQuadrant.us