V100, the firmware is known to be broken and not allowing to simultaneously
open disk devices, causing attempts to boot from a mirror or RAIDZ to cause
a crash. This will be worked around later. The firmwares of newer sun4u models
don't seem to exhibit this problem though.
Steps for ZFS booting:
1. create VTOC8 label
# gpart create -s vtoc8 da0
2. add partitions, f.e.:
# gpart add -t freebsd-zfs -s 60g da0
# gpart add -t freebsd-swap da0
resulting in something like:
# gpart show
=> 0 143331930 da0 VTOC8 (68G)
0 125821080 1 freebsd-zfs (60G)
125821080 17510850 2 freebsd-swap (8.4G)
3. create zpool
# zpool create bunker da0a
or for mirror/RAIDZ (after preparing additional disks as in steps 1. + 2.):
# zpool create bunker mirror da0a da1a
# zpool create bunker raidz da0a da1a da2a ...
4. set bootfs
# zpool set bootfs=bunker bunker
5. install zfsboot
# zpool export bunker
# gpart bootcode -p /boot/zfsboot da0
6. write zfsloader to the ZFS Boot Block (so far, there's no dedicated tool
for this, so dd(1) has to be used for this purpose)
When using mirror/RAIDZ, step 4. and the dd(1) invocation should be repeated
for the additional disks in order to be able to boot from another disk in
case of failure.
# sysctl kern.geom.debugflags=0x10
# dd if=/boot/zfsloader of=/dev/da0a bs=512 oseek=1024 conv=notrunc
# zpool import bunker
7. install system on ZFS filesystem
Don't forget to set 'zfs_load="YES"' and vfs.root.mountfrom="zfs:bunker" in
loader.conf as well as 'zfs_enable="YES"'in rc.conf.
8. copy zpool.cache to the ZFS filesystem
cp -p /boot/zfs/zpool.cache /bunker/boot/zfs/zpool.cache
9. set mountpoint
# zfs set mountpoint=/ bunker
10. Now, given that aliases for all disks in the zpool exists (check with
the `devalias` command on the boot monitor prompt) and disk0 corresponds
to da0 (likewise for additional disks), the system can be booted from the
ZFS with:
{1} ok boot disk0
PR: 165025
Submitted by: Gavin Mu
