ZFSBootSlice [FreeBSD WIKI]

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====== Installing FreeBSD Root on ZFS using a FreeBSD MBR Slice ======

<callout type="warning">
This guide is a work in progress and hasn't been fully tested
</callout>

<callout type="warning">
**Fails to boot**
</callout>

<code>
BTX loader 1.00  BTX version is 1.02
Consoles: internal video/keyboard
BIOS drive C: is disk0
BIOS 638kB/2094720kB available memory

FreeBSD/i386 bootstrap loader, Revision 1.1
(root@, Sat Jul 18 10:58:41 UTC 2009

can't load 'kernel'

Type '?' for a list of commands, 'help' for more detailed help.
</code>

===== Creating a bootable ZFS Filesystem =====

  - Boot %%FreeBSD%% install DVD or USB Memstick

  - Choose Fixit option in sysinstall

  - Create MBR disk \\ \\ 

If you are installing on an New drive, you will need to create the MBR geometry first:

<code>
Fixit# gpart create -s mbr ad0
</code>

  - Create Slice using gpart\\ \\ 

This example already has two slices defined on the drive.

<code>
Fixit# gpart show ad0
=>       63  625142385  ad0  MBR  (289G)
         63  209712447    1  !7  (100G)
  209712510     417690    2  !136  (204M)
  210130200  415012248       - free -  (198G)
</code>

Create a third slice then create a BSD partition table on the new slice.

<code>
Fixit# gpart add -t freebsd ad0
ad0s3 added
</code>

And examine the result:

<code>
Fixit# gpart show ad0
=>       63  625142385  ad0  MBR  (289G)
         63  209712447    1  !7  (100G)
  209712510     417690    2  !136  (204M)
  210130200  415012248    3  freebsd  (198G)
</code>

Sizes and offsets are specified in sectors (1 sector is typically 512 bytes) but can also be specified in MB or GB by adding an 'M' or 'G' suffix.

  - Set partition active (Optional)\\ \\ 

Some BIOSes might require setting a Slice active.  Here we set partition 1 (the Windows Partiton) as the active partition.

<code>
Fixit# gpart set -a active -i 1 ad0
</code>

  - Load ZFS kernel module

<code>
Fixit# kldload /mnt2/boot/kernel/opensolaris.ko
Fixit# kldload /mnt2/boot/kernel/zfs.ko
</code>

  - Create ZFS Pool zroot

<code>
Fixit# mkdir /boot/zfs
Fixit# zpool create zroot /dev/ad0s3
Fixit# zpool set bootfs=zroot zroot
</code>

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

  - Create ZFS Swap volume

<code>
Fixit# zfs create -V 2gb zroot/swap
Fixit# zfs set org.freebsd:swap=on zroot/swap
Fixit# zfs set checksum=off zroot/swap
</code>

  - Install boot Manager

<code>
Fixit# gpart bootcode -b /mnt2/boot/boot0 ad0
ad0 has bootcode
</code>

It's ok if you get an "unknown class" message here, but it you get "failed to install" or the like, you'll need to try again after making sure that nothing is mounted from /dev/ad0.

  - Install ZFS boot\\ 

- Export zroot, before installing boot code

<code>
Fixit# zpool export zroot
</code>

- Install the boot1 stage:

<code>
Fixit# dd if=/mnt2/boot/zfsboot of=/dev/ad0s3 count=1
</code>

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:

<code>
Fixit# sysctl kern.geom.debugflags=0x10
</code>

- Install the boot2 zfs stage into the convienient hole in the ZFS filesystem on-disk format which is located just after the ZFS metadata (this is the seek=1024).

<code>
Fixit# dd if=/mnt2/boot/zfsboot of=/dev/ad0s3 skip=1 seek=1024
</code>

- Import zroot to continue the install

<code>
Fixit# zpool import zroot
</code>

===== Installing FreeBSD to the ZFS filesystem =====
{{page>RootOnZFS/InstallingFreeBSD&nofooter&noeditbtn}}

===== Finish install =====

  - Create /etc/fstab

<code>
Fixit# cat << EOF > /zroot/etc/fstab
# Device			Mountpoint		FStype	Options		Dump	Pass#
EOF
</code>

  - export LD_LIBRARY_PATH 

<code>
Fixit# export LD_LIBRARY_PATH=/mnt2/lib 
</code>

  - Unmount all zfs filesystems

<code>
Fixit# zfs unmount -a
</code>

  - Change mount points for zroot pool 

<code>
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
</code>

  - Exit Fixit mode, and then sysinstall.  Remove the %%FreeBSD%% install DVD/Memstick and the system will boot using the ZFS root.

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