fix remote degraded gmirror

[Robin Becker]

.........
> 
> a simple
> 
> dd if=/dev/zero of=/dev/adX bs=1M count=1
> 
> would fix that if nothing else
> 
> if there's was no existing label, there is nothing to do except gmirror man
> instructions.  Gmirror is block level mirroring which why no other steps are
> needed.
> 
well now I really need advice, the data centre guy successfully inserted another 
disk in the right place and it appears to be the same model. However, smartctl 
-a /dev/ad4 seems to show a number of errors and many of the indicators are 
prefail or old_age.

In addition the disk doesn't have exactly the same length so when I tried to 
insert gmirror complains that it is too small.

What are my options?
-- 
Robin Becker