On 15/10/2013 15:14, peter@steinhoff.se wrote:

Thanks Brian.

Yes, I replaced sdh because it showed read errors in dmesg and was 
kicked out of the array.

But has the new sdh been rebuilt completely? If that case there should 
be n-1 drives? Or does "spare" just means that it can be used but has 
no data yet?

That's what I'm not sure about. It is "clean" but it is also "spare". 
I'm not sure what state would be seen while it is rebuilding.

When the old sdh had a problem, did you mdadm /dev/mdXXX --fail /dev/sdh?

And after you inserted the new drive, and presumably did mdadm 
/dev/mdXXX --add /dev/sdh, did you see it start to rebuild in /proc/mdstat?

Also I have my old sdh with data on it but I don't know how current 
that data is but perhaps I can use that somehow?

You could mdadm --examine it, but I suspect that the event count will be 
way out of line by now.