[CentOS] 3ware disk failure -> hang

[Joshua Baker-LePain]

On Fri, 6 Jan 2006 at 9:39am, Bryan J. Smith wrote

> Had you used the 3Ware's intelligent hardware RAID, it would
> have hidden the drive disconnect from the system.  You'd see
> a log entry on the failure, and that the array was in a
> "downgraded" state.
>
> Instead, you're using software RAID, and it's up to the
> kernel to not panic on itself because a disk is no longer
> available.  The problem isn't the 3Ware controller, it's the
> software RAID logic in the kernel.

Yes, I'm aware of all that.  I've been using 3wares for *years* (as 
giggle would easily have revealed).  But, as the archives of this list 
will attest to, using these boards in hardware RAID mode in centos 4 is 
bad news.  Performance sucks.  There's some sort of nasty interaction 
between the 3wares and ext3 which makes the combo unusable, really.  And 
we all know the upstream provider's stance on XFS.

>> Having the system hang every time a disk dies is, well, less
>> than optimal.
>
> No joke.  It wasn't until even kernel 2.6 that hotplug
> support was offered, and it still does _not_ work as
> advertised.

Hotplug worked just fine on this system when I tested (multiple times) via 
'mdadm -f -r' and 'mdadm -a'.  It's the actual disk failure handling 
that's at fault here.

-- 
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University