Booting from ZFS raidz
dfr at rabson.org
Wed Dec 17 10:25:54 PST 2008
I've been working on adding raidz and raidz2 support to the boot code
and I have a patch which could use some testing if anyone here is
interested. This http://people.freebsd.org/~dfr/
raidzboot-17122008.diff adds support for raidz and raidz2. The easiest
way to prepare a bootable pool is to put a GPT boot partition on each
disk that will make up the raidz pool and install gptzfsboot on the
boot partition of every drive.
You can boot from any of the drives and as long as the BIOS can see
enough drives you should be able to boot. The boot code supports
booting from degraded pools and pools where some of the data is
corrupt (as long as it has enough data available to repair the problem).
Currently the ZFS kernel code refuses to allow you to set the bootfs
pool property on raidz pools (because Solaris can't boot from them).
This means that you are limited to booting from the root filesystem of
the pool for now (it shouldn't be hard to relax this restriction). The
root filesystem of the pool should contain a directory /boot with the
usual contents which must include a /boot/loader which was built with
the 'LOADER_ZFS_SUPPORT' make option.
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