linuxexpert-practice-labs/labs/rhcsa/5-3-mounting-at-boot

RHCSA 5.3: Mounting by UUID or label

Mounting file systems at boot by UUID and by label, and finding a bad /etc/fstab line without rebooting.

Before you start

The lab adds two empty 1 GiB spare disks, /dev/loop40 and /dev/loop41. They're image files under /var/lib/le-lab/disks/, attached again at every boot, before file systems are mounted. Use them whole or partition them.

It also adds a line to /etc/fstab for a UUID that doesn't exist, at /mnt/archive. That line has nofail, so it doesn't stop the boot.

Tasks

1. Make an XFS file system on a spare disk (or a partition or LV on it) and mount it on /data at every boot, by UUID.
2. Make an ext4 file system labeled backups and mount it on /backups at every boot, by label.
3. Find the bad /mnt/archive line without rebooting, then remove it. findmnt --verify should then report no errors and no warnings.

Hints

• mkfs.xfs, blkid, a line UUID=... /data xfs defaults 0 0, then systemctl daemon-reload and mount -a.
• mkfs.ext4 -L backups, or e2label; LABEL=backups /backups ext4 defaults 0 2.
• findmnt --verify marks the bad line with [E]; run systemctl daemon-reload after editing /etc/fstab. Run findmnt --verify as root: as a normal user it can't read the devices and warns cannot detect on-disk filesystem type (Permission denied) for every line.