strange ZFS v28 states after disk upgrades/rebuilds

[Dmitry Morozovsky]

On Sun, 21 Aug 2011, Vladislav V. Prodan wrote:

> > - zpool import -F. Allows to rewind corrupted pool to earlier
> >    transaction group.
> > 
> > However, the pool does not seem to be corrupted, at least its contents;
> > after
> > backup is finished, I'll try to reassure by running scrub.
> > 
> 
> In your case, the pool in a state of "DEGRADED" and it can only be repaired by
> stripping transaction history.
> Sometimes it helps to zpool scrub <pool>, but only in the case of loose HDD.

FWIW, replace the component with only one UNAVAIL line has been finished ok 
(UNAVAIL line disappeared together with "replacing" one); and for strange set 
of multiple UNAVAIL I'd overcome this by `zpool detach' all UNAVAIL components 
but one and then `zpool replace' the last one.

What bothers me is (actually, two things, hence are):
- how this situation could have place at the first time
- what leads to locks requiring hard resets

Unfortunately, this motherboard has dead com port, so no much luck for the 
serial console -- or can it be assigned to one of puc() card I have?

-- 
Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
[ FreeBSD committer:                                 marck at FreeBSD.org ]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru ***
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