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

Tue Mar 12 08:30:25 UTC 2013
Arun Khan <knura9 at gmail.com>

On Thu, Mar 7, 2013 at 12:07 AM, Gordon Messmer  wrote:
> On 03/06/2013 08:35 AM, Arun Khan wrote:
>> Any preference between 1 and 2 above.
> Based on about 10 years of running a hundred or so systems with 3ware
> controllers, I would say that you're better off with an LSI MegaRAID
> card, or with Linux software RAID.  3ware cards themselves have been the
> most problematic component of any system I've run in my entire
> professional career (starting in 1996).  Even very recent cards fail in
> a wide variety of ways, and there is no guarantee that if your array
> fails using a controller that you buy now that you'll be able to connect
> it to a controller that you buy later.

@ Gordon - thanks for sharing this piece of info!  In case of RAID
card failure, it is important to be able to recover the data (RAID
device) with a compatible replacement.    Are the LSI MegaRAID
controller more reliable in this respect?

> At this point, I deploy almost exclusively systems running Linux with
> KVM on top of software RAID.  While I lose the battery backed write
> cache (which is great for performance unless you sustain enough writes
> to fill it completely, at which point the system grinds nearly to a
> halt), I gain a consistent set of management tools and the ability to
> move a disk array to any hardware that accepts the same form factor
> disk.  The reliability of my systems has improved significantly since I
> moved to software RAID.

Software RAID is an option but I don't think hot swap is possible
without some tinkering with the mdadm tool a priori.
The systems will go to client site (remote),  prefer to keep the
support calls to remove/replace hardware activity :(

-- Arun Khan