Re: Accessing disks via their serial numbers.

On Tue, Jun 27, 2006 at 06:03:12PM +1000, Peter Jeremy wrote:
On Mon, 2006-Jun-26 18:46:19 +0000, Poul-Henning Kamp wrote:
4. It prevents cold-state swapout of disk drives.

Why?

Because /etc/fstab contains the serial number of the disk you just
junked and the new one has a different serial number.

I've used a couple of OSs that derived their logical disk name (ie
/dev/disk/dsk5) from the WWID by keeping a magic database to map
the WWID to the name. None of them have good solutions to telling
the OS that WWID-x has died and I want WWID-y to now map to the same
logical device as WWID-x used to.

Actually having the WWID (or similar) as the logical name would make
handling a disk swap really nasty.

Stating that the sysadmin knows about the change doesn't address the
issue: The sysadmin changed the device because the old one failed.
There may or may not have been advance notice of the replacement.

I'm not saying it solves all problems, but it is very useful in certain
situations, where what you mentioned is not the case.

For software RAID you still has to somehow say that this driver replaced
that one.

--
Pawel Jakub Dawidek http://www.wheel.pl
pjd@xxxxxxxxxxx http://www.FreeBSD.org
FreeBSD committer Am I Evil? Yes, I Am!

Attachment: pgpKATNVyN7iw.pgp
Description: PGP signature

Relevant Pages