ZFS Root Won't Mount - Unknown Filesystem
mokomull at gmail.com
Mon Jan 9 01:17:34 UTC 2012
On Sat, Jan 7, 2012 at 7:44 AM, Drew Tomlinson <drew at mykitchentable.net> wrote:
> I'm attempting a new install of 9.0-RC3 amd64. My system has 4 500 GB
> drives. Using this tutorial as a guide:
When I built my ZFS-root system, I did most of these things, except I
had a slightly different setup for the root filesystem itself. What I
did is akin to:
# zpool import -o altroot=/target -o cachefile=/tmp/zpool.cache zroot
# zfs set mountpoint=/ zroot
# cp -a /tmp/zpool.cache /target/boot/zfs/zpool.cache
I did not manually set mountpoints for anything but the root
filesystem. It sounds like manually-set mountpoints are the way most
people do it, but you can try to clear the mountpoints by doing:
# zfs inherit mountpoint zroot/fs
for each filesystem in your root pool.
> I created a boot and a freebsd-zfs partition on each drive. Then I created
> a raid1z pool using all 4 drives. I followed the rest of the tutorial
> exactly and ensured that I copied the zpool.cache to boot/zfs.
> When I try to boot my new system, it all goes fine up until it's time to
> mount zfs:zroot. It fails with an "error 2" "unknown filesystem" error. I
> don't know if this means anything but at the mountfrom prompt, the system
> will not accept any keyboard input. Same keyboard works fine when booted
> into LiveCD.
I had that same problem with mine for a while, and it turned out that
importing with the "altroot" option implies "cachefile=none"; until I
realized I needed to also specify "cachefile=/some/path", I had
accidentally ended up with a /boot/zpool.cache that didn't actually
reference any zpools.
> Unfortunately because I can't figure out how to get a LiveCD type
> environment with sshd running, I can't copy and paste exact error messages
> or command outputs.
I was using PXE/NFS booting to install this machine, so unfortunately
I can't help you here.
> I've searched and the two things that seem to be important are that there's
> a zpool.cache file and that the zfs partitions are correct. A 'gpart show
> -l' shows my partitions something close to this:
> 34 <big number> ada0 GPT (456G)
> 34 128 1 null (128K)
> 162 <big number> 2 disk0 (456G)
> What have I done wrong and what do I need to do to get my zfs:zroot pool
> mounted as root?
It sounds like you're almost there! My guess is that the cache file
is what is missing/incorrect.
Reading over some man pages, make sure you don't do a "zpool export"
before you copy the cache file; exporting the array removes it from
the cache and/or deletes the cache file entirely.
If you end up with a LiveCD that lets you copy these things, it might
help to see
# zpool list -o name,altroot,cachefile
# zpool status
# zfs list -o name,mountpoint,mounted
Hope some of this helps.
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