[CentOS] mdraid vs hardware raid, was: Looking for a life-save LVM Guru

Sun Mar 1 22:04:17 UTC 2015
Chris Murphy <lists at colorremedies.com>

On Sat, Feb 28, 2015 at 5:14 PM, Chris Murphy <lists at colorremedies.com> wrote:
> "Drives, and hardware RAID cards are subject to firmware bugs, just as
> we have software bugs in the kernel." makes no assessment of how
> common such bugs are relative to each other.

I don't want to underestimate the value of good hardware RAID with
BBWC implementations when it comes to avoiding problems that aren't
bugs, but are "just the way things are." For example unclean
shutdowns, and especially unclean shutdowns along with a device
failure.

There's a metric ton of really useful information in the man 4 md page
that most people probably aren't aware of because they usually read
the mdadm page.
http://linux.die.net/man/4/md

Relevant in this case is the Unclean Shutdown section. It's completely
rational for people to think, hmmm, maybe I'd rather get a hardware
RAID card that supports BBWC to avoid some of these problems? Plus
then you get to use no barriers, resyncs and degraded operation can
have much lower performance penalty, etc.

-- 
Chris Murphy