Installing FreeBSD Root on ZFS using GPT

WARNING! these directions will not work with bsdinstall based media (9.0-BETA1+) due to changes in distfile layout, pathing, and version numbering.

1. Creating a bootable ZFS Filesystem

  1. Boot FreeBSD install DVD or USB Memstick
  2. Choose Fixit option in sysinstall
  3. Create GPT Disk
     Fixit# gpart create -s gpt ad0


    • If the disk already contains a partitioning scheme, and this scheme would first need to be destroyed using:
     Fixit# gpart destroy ad0
  4. Create the boot, swap and zfs partitions
     Fixit# gpart add -s 128K -t freebsd-boot ad0
     Fixit# gpart add -s 4G -t freebsd-swap -l swap0 ad0
     Fixit# gpart add -t freebsd-zfs -l disk0 ad0

    This creates 3 partitions. The first partition will contains the gptzfsboot loader which will be able to load /boot/loader or /boot/zfsloader (9.0-CURRENT) from a ZFS partition. The second partition is a 4 GB swap partition. The third partition is dedicated to the ZFS zpool and uses the remaining space on the disk.


    1. While a ZFS Swap Volume can be used instead of the freebsd-swap partition, crash dumps can't be saved to the ZFS Swap Volume.

  5. Install the Protective MBR (pmbr) and gptzfsboot loader
     Fixit# gpart bootcode -b /mnt2/boot/pmbr -p /mnt2/boot/gptzfsboot -i 1 ad0
    This may fail with an "operation not permitted" error message, since the kernel likes to protect critical parts of the disk. If this happens for you, run:
     Fixit# sysctl kern.geom.debugflags=0x10
  6. Load ZFS kernel module
     Fixit# kldload /mnt2/boot/kernel/opensolaris.ko
     Fixit# kldload /mnt2/boot/kernel/zfs.ko
  7. Create ZFS Pool zroot
     Fixit# mkdir /boot/zfs
     Fixit# zpool create zroot /dev/gpt/disk0
     Fixit# zpool set bootfs=zroot zroot


    • zroot is the name of the ZFS Pool, it could be anything (i.e. tank, data, ...)

2. Installing FreeBSD to the ZFS filesystem

  1. Create ZFS filesystem hierarchy

    The fletcher4 algorithm should be more robust than the fletcher2 algorithm.

     Fixit# zfs set checksum=fletcher4                                      zroot
     Fixit# zfs create -o compression=on    -o exec=on      -o setuid=off   zroot/tmp
     Fixit# chmod 1777 /zroot/tmp
     Fixit# zfs create                                                      zroot/usr
     Fixit# zfs create                                                      zroot/usr/home
     Fixit# cd /zroot ; ln -s /usr/home home
     Fixit# zfs create -o compression=lzjb                  -o setuid=off   zroot/usr/ports
     Fixit# zfs create -o compression=off   -o exec=off     -o setuid=off   zroot/usr/ports/distfiles
     Fixit# zfs create -o compression=off   -o exec=off     -o setuid=off   zroot/usr/ports/packages


    If you use nullfs or nfs to mount /usr/ports to different locations/servers, you will also need to nullfs/nfs mount /usr/ports/distfiles and/or /usr/ports/packages.

     Fixit# zfs create -o compression=lzjb  -o exec=off     -o setuid=off   zroot/usr/src
     Fixit# zfs create                                                      zroot/var
     Fixit# zfs create -o compression=lzjb  -o exec=off     -o setuid=off   zroot/var/crash
     Fixit# zfs create                      -o exec=off     -o setuid=off   zroot/var/db
     Fixit# zfs create -o compression=lzjb  -o exec=on      -o setuid=off   zroot/var/db/pkg
     Fixit# zfs create                      -o exec=off     -o setuid=off   zroot/var/empty
     Fixit# zfs create -o compression=lzjb  -o exec=off     -o setuid=off   zroot/var/log
     Fixit# zfs create -o compression=gzip  -o exec=off     -o setuid=off   zroot/var/mail
     Fixit# zfs create                      -o exec=off     -o setuid=off   zroot/var/run
     Fixit# zfs create -o compression=lzjb  -o exec=on      -o setuid=off   zroot/var/tmp
     Fixit# chmod 1777 /zroot/var/tmp


    1. Compression may be set to on, off, lzjb, gzip, gzip-N (where N is an integer from 1 (fastest) to 9 (best compression ratio. gzip is equivalent to gzip-6).
    2. Compression will cause some latency when accessing files on the ZFS filesystems. Use compression on ZFS filesystems which will not be accessed that often.

  2. Install FreeBSD to zroot
     Fixit# cd /dist/8.0-*
     Fixit# export DESTDIR=/zroot
     Fixit# for dir in base catpages dict doc games info lib32 manpages ports; \
              do (cd $dir ; ./ ; done
     Fixit# cd src ; ./ all
     Fixit# cd ../kernels ; ./ generic
     Fixit# cd /zroot/boot ; cp -Rlp GENERIC/* /zroot/boot/kernel/
  3. Make /var/empty readonly
     Fixit# zfs set readonly=on zroot/var/empty
  4. chroot into /zroot
     Fixit# chroot /zroot
  5. Create /etc/rc.conf
     Fixit# echo 'zfs_enable="YES"' > /etc/rc.conf
     Fixit# echo 'hostname="beastie.mydomain.local"' >> /etc/rc.conf
     Fixit# echo 'ifconfig_re0="DHCP"' >> /etc/rc.conf


    • Replace re0 with the name of the Network interface for the new system
  6. Create /boot/loader.conf
     Fixit# echo 'zfs_load="YES"' > /boot/loader.conf
     Fixit# echo 'vfs.root.mountfrom="zfs:zroot"' >> /boot/loader.conf
  7. Change root's password
     Fixit# passwd
  8. Set the local time zone
     Fixit# tzsetup
  9. Create /etc/mail/aliases.db
     Fixit# cd /etc/mail
     Fixit# make aliases
  10. Exit from the /zroot
     Fixit# umount /dev
     Fixit# exit
  11. Install zpool.cache to the ZFS filesystem
     Fixit# cp /boot/zfs/zpool.cache /zroot/boot/zfs/zpool.cache

3. Finish install

  1. Create /etc/fstab
     Fixit# cat << EOF > /zroot/etc/fstab
     # Device                       Mountpoint              FStype  Options         Dump    Pass#
     /dev/gpt/swap0                 none                    swap    sw              0       0
  2. export LD_LIBRARY_PATH
     Fixit# export LD_LIBRARY_PATH=/mnt2/lib 
  3. Unmount all zfs filesystems
     Fixit# zfs unmount -a
  4. Change mount points for zroot pool
     Fixit# zfs set mountpoint=legacy zroot
     Fixit# zfs set mountpoint=/tmp zroot/tmp
     Fixit# zfs set mountpoint=/usr zroot/usr
     Fixit# zfs set mountpoint=/var zroot/var
  5. Exit Fixit mode, and then sysinstall. Remove the FreeBSD install DVD/Memstick and the system will boot using the ZFS root.

RootOnZFS/GPTZFSBoot (last edited 2016-10-27 20:30:46 by LiWenHsu)