Caveat emptor: Beware of ZFS on HEAD

[Peter Wemm]

We mostly run HEAD in the freebsd.org cluster.  Sometime in the last few weeks 
an ugly zfs problem has surfaced. If a redundant volume is degraded, zfs 
panics on boot.  If a drive fails while running, or is manually put offline, zfs 
panics the same way.

I do not have a smoking gun, but I am suspicious of the June 28th commits 
(starting at r320156) and their follow-ups. eg: r320452.

https://bugs.freebsd.org/220691

I believe single disk systems will *not* be affected by this - the panic only 
happens when a raidz (and presumably mirror) degrades.  Your laptop etc should 
be fine.

I apologize for being vague - I do not know more. Folks running HEAD should 
take appropritate precautions (eg: keeping a known-good kernel.old and modules 
around).  This is always advisable when running HEAD anyway, particularly so 
now.  For us, a kernel.old from June 18th worked fine.

-- 
Peter Wemm - peter at wemm.org; peter at FreeBSD.org; peter at yahoo-inc.com; KI6FJV
UTF-8: for when a ' or ... just won\342\200\231t do\342\200\246
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 488 bytes
Desc: This is a digitally signed message part.
URL: <http://lists.freebsd.org/pipermail/freebsd-current/attachments/20170712/b468c106/attachment.sig>