FreeNAS root on ZFS

[HarryE]

As I am a big fan of ZFS, I tweaked FreeNAS to boot&run completely from ZFS. No UFS at all. On a single 2Gb stick, root filesystem takes 431Mb on ZFS.
Having root on ZFS brings the advantages of customization of the filesystem (rw root) without the worries of "pulling-the-plug" solved by read-only root +MD of nanobsd.
The upgrades/downgrades could be simple zfs receive or clone/rollbacks.


The web interface doesn't see the zpool but sees the snapshots in root zfs.
I suppose I have to go into some sqlite db and manually add something, since the autoimport doesn't work for active zpools.

Any ideas on how to do this?

 

[survive]

Hi HarryE,

Sounds like a very cool project you have going on there. Be sure to let us know what you find out!

-Will

 

[HarryE]

Almost there...

Here it is:
I used my regular FreeBSD 8.2 to create 3 partitions on a 2GB stick as described in FreeBSD's Root-on-zfs tutorial, 1 for bootstrap, one for swap, and one for zpool.
Then I created the zpool, named it nanozfs to please the two worlds . Inside I created 3 zfs filesystems named nanozfs/part1, nanozfs/cfg and nanozfs/data.
Next I copied the content of the FreeNAS partitions from another stick into nanozfs/part1, nanozfs/cfg and nanozfs/data filesystems accordingly.
Adjusted loader.conf, fstab, rc.conf and created a necessary fsck_zfs (as a simple exit 0). Removed /conf/default/etc/remount.
At some point there was a "zpool set bootfs=nanozfs/part1 nanozfs" involved.
Since then I found the necessary tables to be modified in order to manually import zfs filesystems into web interface.
In the morning I'll download a newer version of FreeNas, create a nanozfs/part2 filesystem, copy the content + tweaks into it.
Then snaphot nanozfs/cfg, nanozfs/data just in case I want to rollback.
A zpool set bootfs=nanozfs/part2 nanozfs will help to boot the new version.

 

[liveisousb]

Hey HarryE, have you been able to do this for 9.2.1.8?

I've only been able to do a hacky workaround.

!! THIS IS PROBABLY TOTALLY UNSUPPORTED USE AT YOUR OWN RISK !!

Setup:
- machine has small internal drive as /dev/ada0 and boot from a "liveisousb"
- boot into mfsBSD from liveisousb
- setup /dev/ada0 with a zpool "autoroot" mounted to /mnt
- copy mfsBSD's mfsroot to /mnt/
- copy FreeNAS USB image to /mnt/
- copy FreeNAS /boot to /mnt/
- copy a chroot script to /mnt/
- reboot

How it works:
- when the system boots up from /dev/ada0
- loads mfsroot into RAM
- script does zpool import autoroot
- runs chroot script
- FreeNAS running USB image is mounted as /freenas
- /cfg and /data is mounted on /freenas/cfg and /freenas /data
- devfs is mounted as /freenas/dev
- FreeNAS continues boot from /freenas/etc/rc

I tried to simplify it with a script which you will need to modify to suit your environment:
https://github.com/johnko/johnko.github.io/blob/master/posts/tech/20141005-freenas-on-zfs-root.md
https://github.com/johnko/johnko.github.io/blob/master/scripts/mfsbsd-freenaszfs.sh

 

[mjws00]

Heh. Is that better than running 9.3 alpha? Nice necro. Like the script and mfsbsd. :)

 

[cyberjock]

Sorry, I'm gonna lock this thread. It's more than 3 years old. There is no reason to pull up a thread that old with a question. :P

This will be part of 9.3, so be patient. Or go grab the alpha builds and give them a try. :)

 

[solarisguy]

May be instead of a locked thread, someone who knows/understands ZFS root changes in 9.3 would explain them here. The thread title and posts seem to be relevant, just FreeNAS 9.3 took a different(?) route.