device names changes for adX.

[Matthew Seaman]

On 02/10/2010 15:29:49, Peter Ankerstål wrote:

>> Peter Ankerstål wrote:

>>> When I installed FreeBSD 8.1-RELEASE (freebsd-update) the adX devices changed index number and
>>> the machine obviously didnt boot. Due to this I hesitate to install 8.1 on my servers remote. How do I know
>>> if and to what the devices will change?

>> label your filesystems and mount them by label rather than by device name. see
>>
>> man glabel

> Thanks, I may try that. But how will this affect ZFS raidz set up to use ad-drives?
> 
> Like this:
> 
> 	tank        ONLINE       0     0     0
> 	  raidz1    ONLINE       0     0     0
> 	    ad10s2  ONLINE       0     0     0
> 	    ad12    ONLINE       0     0     0
> 	    ad14    ONLINE       0     0     0
> 	    ad16    ONLINE       0     0     0

It actually shouldn't matter.  ZFS writes metadata about the zpools,
zdevs etc. it knows about onto the drives, and if it can read the drive
and see the metadata, it can reconstruct itself.  You can take disks out
of a ZFS setup, shuffle them, stick them back into the wrong slots, and
ZFS will still work.  Similarly, you can use glabel to name the disks,
and switch to using that, and everything should still work.

In fact, if you glabel the disks while ZFS is still active, it should
instantly recognise all the new names and update the 'zpool status'
output on the fly.  Actually, that last is probably the right way to do
things -- you'll update the zpool.cache that way, which means that ZFS
will come up without any remedial action after reboot.

	Cheers,

	Matthew

-- 
Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
JID: matthew at infracaninophile.co.uk               Kent, CT11 9PW

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