LPIC-2 Linux Kernel and System Startup Practice Question
Exhibit
Refer to the exhibit. [ 0.000000] Kernel command line: BOOT_IMAGE=/vmlinuz-5.10.0-8-amd64 root=/dev/sda1 ro quiet [ 1.234567] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(8,1) [ 1.234568] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-8-amd64 #1 [ 1.234569] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b_prebuilt.qemu.org 04/01/2014
A system fails to boot with the error shown. Which kernel parameter should be added to the kernel command line to resolve the issue?
⚠ Common exam trap
The trap here is that candidates often focus on correcting the root device path or filesystem type, overlooking that the real issue is a timing problem where the storage device is not yet ready when the kernel tries to mount it.
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
✓
rootdelay=10
The error indicates that the system cannot find the root filesystem, often because the storage device is not ready when the kernel attempts to mount it. Adding `rootdelay=10` instructs the kernel to wait 10 seconds before attempting to mount the root device, giving USB, SCSI, or other slow-to-probe controllers time to initialize. This is a common fix for boot failures on systems with external or hot-pluggable storage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
root=/dev/sda1
Why it's wrong here
Already present in the command line; the kernel knows the root device but can't access it.
- ✗
noprompt
Why it's wrong here
Disables prompts; irrelevant to the mount failure.
- ✗
rootfstype=ext4
Why it's wrong here
Specifies filesystem type, but the panic indicates missing device, not invalid superblock.
- ✓
rootdelay=10
Why this is correct
Adds a delay before attempting to mount root, allowing the device to become ready.
- ✗
single
Why it's wrong here
Boots into single-user mode; does not fix device detection.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-2 practice question is part of Courseiva's free LPI 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 LPIC-2 exam.