changing file system names

[Charles Jones]

Robert Holtzman wrote:
> Just had occasion to look at my /etc/mtab and the file system names had 
> changed from /dev/sda* to /dev/sdb*. My /etc/fstab still shows /dev/sda*.
> This may have happened when I recently used gparted to create 3 new 
> partitions (which I have yet to designate labels or mount points for).
> What happened and can I rename back to /dev/sda* or do I live with it and
> edit /etc/fstab?
>
> The danger, of course, is that if anything happened that would force me to 
> reboot, such as a power outage, I'd be screwed....I think.
>
> Any pointers *greatly* appreciated!
>   
I'm a bit confused as to how your devices could have changed from sda to 
sdb while your system was running? Its sounds more likely that the 3 new 
partitions you created were on sdb. Either way you could simply things 
by mounting via labels or UUIDs.  Check the man page on "e2label" for 
how to read and create disk labels, then alter your fstab to use labels 
instead of the device names.  Here's a sample from one of my boxes:

# head -2 /etc/fstab
LABEL=/                 /                       ext3    defaults        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2

Note: for testing if the labels work before you reboot, you should be 
able to do a "mount -a" and nothing will happen if there are no errors, 
or if you call mount specifically for a mountpoint, like "mount /", you 
will get an "error" similar to:
# mount /
mount: /dev/sda1 already mounted or / busy
mount: according to mtab, /dev/sda1 is already mounted on /

This output indicates that mount did successfully find the device and 
try to mount it, so the fstab entry is good. And should mount fine upon 
reboot.

P.S. Make a backup copy of your /etc/fstab before you start changing 
anything. Probably also a good idea to save a copy of the output of 
"mount" and/or your current /etc/mtab

-Charles