Thanks for your comments Emmanuel.
> So the RAID array looks OK, the RAID controller doesn't report any
> particular problem. You said it was reported as 0 K. Where did you see
> 0 K reported?
No I meant it is "OK" with "O" :)
> What gives "dmesg | grep 3w-9xxx" ? and "tw_cli alarms" ? Was the
> filesystem under heavy write when the problem occured ?
The server has been restarted since the problems started, so nothing
notable in "tw_cli alarms" or dmesg. The controller was performing
rebuild on another the other unit when it happened, however I don't
think the actual xfs-filesystem was particularly loaded.
> I'd start with launching a RAID verify, to detect and correct possible
> on-disk coherency problems (it can't hurt anyway):
> tw_cli /c0/u0 start verify
> Then "tail -f /var/log/messages | grep 3w-9xxx" ...
I will try this over night and see if something is reported.
> I suppose that there are no problems to be discovered. Most probably
> IOs to the array were lost because of the bus reset.
That's what I am afraid of too.