Booting FreeBSD from ZFS
645 words, 4 minutes
Here are my notes on how to configure a full ZFS-based FreeBSD system. In this particular case, the system is “FreeBSD 9.0-CURRENT #0: Thu May 12 15:34:46 UTC 2011” and it runs on a Dell Inspiron Mini 1012 (Intel Atom N450) with 1GB of RAM. This is just a P.O.C. as it is said that ZFS would required at least 2GB of RAM to perform nicely.
Get the media
I grabbed the FreeBSD-9.0-CURRENT-201105-amd64-memstick.img image from my
nearest mirror and burned it onto an USB stick:
# sudo dd if=FreeBSD-9.0-CURRENT-201105-amd64-memstick.img of=/dev/rdisk2 bs=1m
Stick the USB pen into the laptop and boot from it. When asked the task to
perform, just select “
Summon the daemon
Log in as “root”. On the Live CD, there is no password set.
Run the sysinstall command and configure your keyboard layout ; then exit.
Should you ask yourself, I used “Keymap” / “French ISO (accent)”, then “X Exit
Install”.
Find the name of your disks. I only have one local:
# sysctl kern.disks
kern.disks: da1 da0 ada0
# gpart list | egrep "Geom|Mediasize"
Geom name: ada0
Mediasize: 200038809600 (186G)
Geom name: da0
Mediasize: 65536 (64k)
Mediasize: 735173120 (701M)
Mediasize: 1025506304 (978M)
According to the reported sizes, my local disk is “ada0”. Clean the disk:
# gpart destroy ada0
ada0 destroyed
In my case, the disk contained previous partition layout from various testings
and the gpart destroy command didn’t work. I had to wipe the disk out first:
# dd if=/dev/zero of=/dev/ada0 count=64
# gpart destroy ada0
ada0 destroyed
Create the partition table and the slices:
# gpart create -s gpt ada0
# gpart add -s 128K -t freebsd-boot -l boot ada0
ada0p1 added
# gpart add -s 2G -t freebsd-swap -l swap ada0
ada0p2 added
# gpart add -t freebsd-zfs -l tank ada0
ada0p3 added
Install the boot code to be able to actually boot from the ZFS root:
# gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ada0
bootcode written to ada0
Load the ZFS modules to be able to create and populate the filesystems:
# kldload opensolaris.ko
# kldload zfs.ko
(...)
ZFS filesystem version 5
ZFS storage pool version 28
Create the ZFS pool using the single disk:
# zpool create tank /dev/gpt/tank
# zpool set bootfs=tank tank
Create the FreeBSD tree:
# zfs set checksum=fletcher4 tank
# zfs create -o compression=on -o exec=on -o setuid=off tank/tmp
# chmod 1777 /tank/tmp
# zfs create -o compression=gzip -o dedup=on tank/usr
# zfs create tank/usr/home
# cd /tank; ln -s /usr/home home
# mkdir /tank/var
# cd /tank/var; ln -s /tmp tmp
Have a look at the “source” link below to get smarter directory layout.
Install the FreeBSD content:
# cd /usr/freebsd-dist
# sh -c 'for FIC in *txz; do cat ${FIC} | tar --unlink -xpJf - -C /tank/; done'
Configure FreeBSD:
# chroot /tank
# echo 'zfs_enable="YES"' > /etc/rc.conf
# cat > /boot/loader.conf
vfs.zfs.prefetch_disable="1"
vfs.root.mountfrom="zfs:tank"
zfs_load="YES"
^D
# echo "/dev/gpt/swap none swap sw 0 0" >> /etc/fstab
# passwd root
# tzsetup
# cd /etc/mail; make aliases
# exit
Save the ZFS cache-file:
# cd /boot/zfs
# zpool export tank && zpool import tank
# cp /boot/zfs/zpool.cache /tank/boot/zfs/
Configure the filesystem mount points:
# zfs unmount -a
# zfs set mountpoint=legacy tank
# zfs set mountpoint=/tmp tank/tmp
# zfs set mountpoint=/usr tank/usr
# zfs set mountpoint=/usr/home tank/usr/home
Reboot into FreeBSD and enjoy:
# reboot
Note that the keyboard layout is configured as US on reboot…
Use “sysinstall” to configure the rest of the system.
BTW, the ZFS system goes like this:
# zpool list
NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT
tank 184G 1.03G 183G 0% 1.14x ONLINE -
# zfs list -r -o name,used,avail,refer,mountpoint,compressratio
NAME USED AVAIL REFER MOUNTPOINT RATIO
tank 1.10G 180G 324M legacy 2.02x
tank/tmp 35K 180G 35K /tmp 1.00x
tank/usr 735M 180G 735M /usr 2.57x
tank/usr/home 38.5K 180G 38.5K /usr/home 1.04x
That’s All Folks!