"ad0: TIMEOUT - WRITE_DMA" type errors with 7.0-RC1

Danny Braniss danny at cs.huji.ac.il
Sun Jan 27 05:24:21 PST 2008

> Henri Hennebert wrote:
> > Jeremy Chadwick wrote:
> >> On Fri, Jan 25, 2008 at 06:17:24PM -0700, Joe Peterson wrote:
> >>> Glad you got it back!  Yes, when I was first playing with ZFS, I noti=
> ced
> >>> that booting between single and multi user mode could make the pools
> >>> "invisible".  Import seemed to bring them back...
> >>
> >> I did go into single-user mode and attempt to do ZFS-related commands,=
> >> which might explain the "no datasets available" once I was back in
> >> multiuser!  I would classify that as a bug, and one which is going to
> >> cause all sorts of hair-pulling for administrators in the future.  I
> >> wonder what it's caused by.
> >=20
> > In single user / is read only and so /boot/zfs/zpool.cache can't be=20
> > created/updated
> But it's still readable. The issue is that hostid isn't set (by=20
> /etc/rc.d/hostid).

if the root is read only, as the case of diskless/dataless boot, it's
the fact that /boot/zfs/zpool.cache cannot be used which causes
the problem, so adding zpool import -a solves the issue.


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