booting off a ZFS pool consisting of multiple striped mirror vdevs

[Robert Noland]

On Mon, 2010-02-15 at 10:07 -0800, Matt Reimer wrote:
> On Sat, Feb 13, 2010 at 12:04 PM, Dan Naumov <dan.naumov at gmail.com> wrote:
> 
> > Hello
> >
> > I have succesfully tested and used a "full ZFS install" of FreeBSD 8.0
> > on both single disk and mirror disk configurations using both MBR and
> > GPT partitioning. AFAIK, with the more recent -CURRENT and -STABLE it
> > is also possible to boot off a root filesystem located on raidz/raidz2
> > pools. But what about booting off pools consisting of multiple striped
> > mirror or raidz vdevs? Like this:
> >
> > Assume each disk looks like a half of a traditional ZFS mirror root
> > configuration using GPT
> >
> > 1: freebsd-boot
> > 2: freebsd-swap
> > 3: freebsd-zfs
> >
> > |disk1+disk2| + |disk3+disk4| + |disk5+disk6|
> >
> > My logic tells me that while booting off any of the 6 disks, boot0 and
> > boot1 stage should obviously work fine, but what about the boot2
> > stage? Can it properly handle booting off a root filesystem thats
> > striped across 3 mirror vdevs or is booting off a single mirror vdev
> > the best that one can do right now?
> >
> >
> I don't know, but I plan to test that scenario in a few days.

It *should* work... I made changes a while back that allow for multiple
vdevs to attach to the root.  In this case you should have 3 mirror
vdevs attached to the root, so as long as the BIOS can enumerate all of
the drives, we should find all of the vdevs and build the tree
correctly.  It should be simple enough to test in qemu, except that the
BIOS in qemu is a little broken and might not id all of the drives.

robert.

> Matt
> _______________________________________________
> freebsd-stable at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-stable
> To unsubscribe, send any mail to "freebsd-stable-unsubscribe at freebsd.org"
-- 
Robert Noland <rnoland at FreeBSD.org>
FreeBSD