[CentOS] [OT/HW] hardware raid -- comment/experience with 3Ware

On 2013-03-06, Arun Khan <knura9 at gmail.com> wrote:
>
> I am looking for a hardware raid card that supports up to 4 SATA II
> hard disks with hot swap (compatible raid cage)
>
> I have short listed two LSI/3Ware cards:
> 1. 9750-4i
> 2. 9650SE-4LPML
>
> I would appreciate your personal experience with the CLI tools
> provided by LSI.
> Can they be configured to send email for disk failures or SMART errors?

Yes, with the 3dm2 monitor.  There was a bug (which may still exist)
where using the hostname of the SMTP server did not work, so you should
try the IP address if you try using a DNS name and it doesn't work.  You
may also want to adjust the EmailSeverity option in 3dm.conf; I use
EmailSeverity 3 which sends me information messages like array
verifications and BBU charging events in addition to disk failures and
SMART errors.  I believe the default setting only sends out errors.

> Is there a Web interface for monitoring?

3dm2 can also provide a web server, though I've never used it.

The command line tools (tw_cli) are okay, but they don't have a fabulous
API.  In particular the output is basically human readable text, which
means you need to do your own text parsing if you want to use the output
in automated tools like nagios.

> Any preference between 1 and 2 above.

I would have a slight preference for the 9750 series.  You get a faster
controller for a very similar price.

The only other thing I would recommend is that you not rely on the
reshape feature of these 3ware cards.  My first test many years ago
actually destroyed the array, and I aborted my second test last year
because the reshape was probably going to take many weeks.  (This was,
IIRC, a reshape from 4 3TB disks to 5.  Linux md can do this reshape in
1-2 days.)  If you need to add space you should use tools like LVM
instead.

The other standard warnings about using these controllers apply (e.g.,
if using the write cache, have a BBU on the card and a UPS on the
server; do regular verifies on your redundant arrays; RAID is not a
backup system).

--keith




-- 
kkeller at wombat.san-francisco.ca.us