hardMultiple Choice
XK0-006 Practice Question: An administrator runs 'mount -a' and receives the…
Exhibit
Refer to the exhibit. # cat /etc/fstab UUID=abc123 / ext4 defaults 0 1 UUID=def456 /boot ext4 defaults 0 2 UUID=ghi789 /home ext4 defaults 0 2 UUID=jkl012 swap swap defaults 0 0 # mount -a mount: /home: special device UUID=ghi789 does not exist.
An administrator runs 'mount -a' and receives the error shown in the exhibit. The /home partition was recently removed and replaced with a new disk. Which of the following steps should the administrator take to resolve the issue?
⚠ Common exam trap
Test-takers frequently assume the filesystem is damaged or needs reformatting (options B or C), when in fact the error stems from a stale UUID reference in /etc/fstab after disk replacement.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Run 'blkid /dev/sda3' to find the new UUID and update /etc/fstab.
The error occurs because the /home partition was replaced with a new disk, so its UUID (or device identifier) in /etc/fstab no longer matches the actual disk. Running 'blkid /dev/sda3' retrieves the new UUID, which must then be updated in /etc/fstab so that 'mount -a' can mount the correct device automatically.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Run 'mount /dev/sda3 /home' to mount the partition manually.
Why it's wrong here
A manual mount bypasses /etc/fstab, so it neither corrects the stale UUID entry nor survives reboot; 'mount -a' would still fail afterwards. It is tempting because manual mounting is the usual quick test for confirming a device is readable, and it would be correct for a one-off temporary mount.
- ✗
Run 'fsck /dev/sda3' to check the filesystem.
Why it's wrong here
Running fsck repairs filesystem inconsistencies on an existing volume, but the exhibit's mount failure stems from a stale UUID or device reference in /etc/fstab after the disk swap, which fsck cannot rewrite. It is tempting because fsck is the standard remedy for corrupt superblocks or unclean shutdowns on a known-good device.
- ✗
Run 'mkfs.ext4 /dev/sda3' to create a new filesystem.
Why it's wrong here
Creating a fresh ext4 filesystem destroys any existing data and still leaves /etc/fstab pointing at the old UUID, so 'mount -a' continues to fail. It is tempting because mkfs is the standard step for genuinely blank replacement disks that have never been formatted, which is not the case here.
- ✓
Run 'blkid /dev/sda3' to find the new UUID and update /etc/fstab.
Why this is correct
Replacing the disk changed the filesystem UUID, so the old UUID in /etc/fstab no longer resolves and mount -a fails. Running blkid /dev/sda3 retrieves the new UUID, which must then replace the stale entry in /etc/fstab.
Visual reference
Go deeper
Related to this question
Key term
Mount
Mounting is the process of making a file system or storage device accessible to a computer's operating system by attaching it to a specific directory in the existing directory tree.
Key term
fstab
fstab is a system configuration file in Linux that defines how and where storage devices and partitions are mounted at boot time.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This XK0-006 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the XK0-006 exam.