gmirror Cannot add disk ad5 to gm0 (error=22)

[Rick C. Petty]

On Thu, Aug 03, 2006 at 11:12:43AM +0200, Miroslav Lachman wrote:
> Rick C. Petty wrote:
> 
> >What other activity is happening on the box?  Are you in the middle of a
> >background fsck?
> 
> Almost no other activities, system has installed apache, mysql, postfix 
> etc., but not serving any requests. Fsck was not running.

But was any other process hitting the disk?  You could try doing the
synchronization in single-user mode and see if the throughput jumps up.

> Now it seems that it is disk problem this time.

[snip]

> After six hours I got message from smartd
> Device: /dev/ad5, FAILED SMART self-check. BACK UP DATA NOW!
> Device: /dev/ad5, 52 Currently unreadable (pending) sectors
> Device: /dev/ad5, 52 Offline uncorrectable sectors

[snip]

> smartd[506]: Device: /dev/ad5, failed to read SMART Attribute Data
> 
> In MRTG graphs I got disk temperature (38?C) and Reallocated Sector 
> Count which is increasing from time of synchronization start and after 5 
> hours the number of reallocated sectors goes above 2000! (out of range 
> of the graph)

This certainly sounds like a disk-related problem.  Likely your previous
failures were due to the same problems.  Time to send the disks back to the
manufacturer for replacement..  :-/

> After manual reboot, there is no ad5 device. I hope new drive helps, but 
> I am still nervous, because I have similar troubles with 2 machines 
> (both replaced with new one - so I played with 4 machines)...

Chance of one "new" disk being bad-- pretty low.
Chance of two new disks being bad-- even lower.
Chance of three or more disks going bad around the same time-- much higher.

I've noticed this type of behavior before.  Someone correct me if I'm
wrong but it appears that you probably got a bad batch of disks.  Try
throwing a different set of disks on the boxes (preferrably a different
manufacturer).  I would also try swapping with brand new high-quality
cables (just because they're cheaper than new disks).

-- Rick C. Petty