Re: Boot from ZFS

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Duncan Young wrote:
| Be carefull,  I've just had a 6 disk raidz array die.  Complete
failure which
| required restore from backup (the controler card which had access to 4
of the
| disks, lost one disk, then a second (at which point the machine
paniced, Upon
| reboot the raidz array was useless (Metadata corrupted)).  I'm also
getting
| reasonably frequent machine lockups (panics) in the zfs code.  I'm
going to
| start collecting crash dumps see if anyone can help in the next week
or two.

That's really unfortunate.  Some sort of automated disk monitoring stuff
would be essential for RAID, this includes RAID-Z.  Did you used the
whole disk dedicatedly for the pool, or (g)labeled before adding it into
the zpool?  Did 'zpool import -f' help?

| I guess what I'm trying to say is, that you can still lose everything
on an
| entire pool, so backups are still essential, an a couple of smaller
pools is
| probably preferable to one big pool (restore time is less).  zfs is
not %100
| (yet?).  The lack of any type of fsck still causes me concern.

It's always true that backup is always important if data is valuable :)
~ The benefit having larger pool is that the administrator would have the
ability to use larger disk space in one ZFS file system (which can not
come cross zpool boundary), but it is recommended that when creating the
zpool, we use smaller raid-z groups, e.g. don't use 48 disks within one
raid-z group, a few disks (like 3-5) within one raid-z group would be fine.

Regarding to fsck, 'zpool scrub' is pretty much like a fsck plus data
integration check.  It would be, however, almost impossible to recover
data if zpool is completely corrupt according to some Sun sources, but
my experience with bad disks within raid-z did not turned me into a
unrecoverable state (yet).

Cheers,
- --
Xin LI <delphij_at_delphij.net>	http://www.delphij.net/
FreeBSD - The Power to Serve!
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