I recently purchased two USB connecting 500Gb drives for server backups.

When I first connected them they appeared as /dev/sda1 for the first and /dev/sdb1 for the second.

The next time I powered them up though the drives appeared on each others mount point , the first drive was now at /dev/sdb1 and the second was at /dev/sda1.

After looking at the mount man page I realised it was possible to mount the drives using their label instead of their device. All it took was a quick edit of /etc/fstab as root , changing :-

/dev/sda1 /mnt/500GbExt1 ext3 defaults,noauto 0 0
/dev/sdb1 /mnt/500GbExt2 ext3 defaults,noauto 0 0

to

LABEL=500GbExt1 /mnt/500GbExt1 ext3 defaults,noauto 0 0
LABEL=500GbExt2 /mnt/500GbExt2 ext3 defaults,noauto 0 0

Now it doesn't matter which USB port or which drives is powered on first , they always appear at the right mount point.

If you don't know the label of the partition , then use e2label to find it :-

e2label /dev/sda1

and perhaps even change it to something more useful :-

e2label /dev/sda1 NewPartitionLabel

I have also moved to UUID's and Volume Names on my workstation , here I have an XFS drive for the MythTV recordings and had to use the xfs_admin command :-

To show the label :-

xfs_admin -l

To change / create a label :-

sudo xfs_admin -L

cool.

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