How To: Use Filesystem Labels in /etc/fstab
Yesterday I have shown how to manage ext2/ext3/ext4 filesystem labels using e2label command. Continuing this topic, let’s update /etc/fstab file on my Ubuntu VM.
WARNING: don’t do this on a real server! try on a non-important virtual machine first, just to learn how to use commands, update fstab and so on. I’m using root filesystem (/) just because that’s the only filesystem I have on my Ubuntu VM.
Here’s how my /etc/fstab looks right now:
root@ubuntu:~ # cat /etc/fstab # /etc/fstab: static file system information. # # Use 'blkid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # / was on /dev/sda1 during installation UUID=ef0ca1f8-28cf-4baf-ada6-f2271aaece17 / ext4 errors=remount-ro 0 1
Check filesystem label for / filesystem
If we run df -h command, we can see what device the root (/) filesystem is using:
root@ubuntu:~ # df -h Filesystem Size Used Avail Use% Mounted on udev 964M 0 964M 0% /dev tmpfs 199M 1.5M 197M 1% /run /dev/sda1 63G 8.7G 51G 15% / tmpfs 991M 0 991M 0% /dev/shm tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 991M 0 991M 0% /sys/fs/cgroup
Let’s use e2label to confirm label for /dev/sda1:
root@ubuntu:~ # e2label /dev/sda1
rootdisk
Perfect! Now that we know /dev/sda1 has label of “rootdisk“, let’s use this label to mount this filesystem going forward.
Update /etc/fstab to use filesystem labels
Editing the /etc/fstab file, comment out the UUID line for / filesystem (note the # at the start of the line now):
# UUID=ef0ca1f8-28cf-4baf-ada6-f2271aaece17 / ext4 errors=remount-ro 0 1
and replace it with this:
LABEL=rootdisk / ext4 errors=remount-ro 0 1
Just to be sure things work as expected, let’s remount the filesystem rather than reboot the server:
root@ubuntu:~ # mount -o remount /
If you don’t get any errors back – this is working as expected.