Re: Drive name slips...

[Andreas Dilger]

Ashok Raj writes:
> Linux kernel names the scsi drives sda, sdb .... so in case you switch
> slots, or move across to a different controller
> then its possible you can have very bad effects. Worst case is removing a
> drive and the drive device files dont have a persistant assiciation with the
> location, or do we have a magic superblock what the configured name was. 
> 
> is there a solution to Linux for this? i was looking at raid, but the config
> file says /dev/sda etc, and it says it does do the superblock magic to avoid
> this. In a SAN its more important as a remote scsi disk may be detectect in
> a different order.

If you are using ext2 filesystems, you can use the ext2 filesystem "label"
instead of the device in /etc/fstab, so you don't get burned by drive name
or address changes.  See mount(8) and fstab(5) for more info (a newer version
of mount is required to support labels).

IMHO, the Solaris/devfs method of specifying drives by
controller/drive/partition is not much better than the current system,
as you still have problems if the SCSI ID is changed, or if you add a
new controller and the controller numbering changes.

Cheers, Andreas
-- 
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert