Root mount from ZFS takes forever...literally.

[James Armstrong]

On Mon, May 17, 2010 at 09:53, Jeremy Chadwick <freebsd at jdc.parodius.com>wrote:

> On Mon, May 17, 2010 at 06:47:02PM +0200, Pawel Tyll wrote:
> > >> Boot process "hangs" on Trying to mount root from zfs:tank/root - I
> > >> can import the pool from alternate boot source (PXE), and access files
> > >> fine, but I can't finish booting the system from ZFS.
> > > What messages do you have on screen when this happens?
> > > Can you upload a screenshot somewhere and post a link?
> > Just mounting root, and nothing happens. System is responsive,
> > attaching/detaching USB keyboard generates messages, and hitting
> > alt+ctrl+del correctly reboots the system.
> >
> > After messing around with fstab (added / entry, bit redundant with
> > loader.conf vfs.root.mountfrom entry) it started to working again, but
> > I can't repeat it now by removing this. Too bad I didn't take a
> > snapshot before fixing :(
> >
> > Strange. :)
>
> Are you *absolutely sure* the problem has to do with ZFS?  I see you
> mention PXE booting......
>
> This sounds much like an environment where serial console is set up
> incorrectly; kernel messages will be seen up to the final "Mounting
> root..." message, but everything past that goes to VGA console (or
> serial console, depends on the configuration mishap).
>
> We've seen a similar issue, Ctrl-T shows a zfs process running, and there
is a lot of activity on some of the disks in our zfs array.

James