LPIC-1 Devices, Filesystems and FHS Practice Question
A junior administrator needs to create a new ext4 filesystem on the partition /dev/sdb2. The partition already exists but has never been formatted. Which command should the administrator run to create the filesystem?
⚠ Common exam trap
Watch out — candidates often confuse partition creation tools like fdisk with filesystem creation tools like mkfs.ext4, when the partition already exists and only needs formatting.
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
✓
mkfs.ext4 /dev/sdb2
Creating a filesystem requires a mkfs-family tool, and the ext4-specific front end is mkfs.ext4. Because the partition exists but is blank, no partitioning step is needed and no mount or repair step applies. The command writes the on-disk structures that make /dev/sdb2 mountable as ext4.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
fsck.ext4 /dev/sdb2
Why it's wrong here
fsck.ext4 checks and repairs an existing ext4 filesystem. On a partition with no filesystem it reports an invalid superblock and offers no way to initialize one. Using it here would at best do nothing and at worst confuse the administrator into thinking the partition is corrupt.
- ✗
mount -t ext4 /dev/sdb2 /mnt
Why it's wrong here
mount attaches an existing filesystem to the directory tree; it does not create one. Because /dev/sdb2 has never been formatted, mount would fail with a bad superblock or unknown filesystem error. The administrator must format the partition before it can be mounted.
- ✓
mkfs.ext4 /dev/sdb2
Why this is correct
mkfs.ext4 is the dedicated front-end for creating an ext4 filesystem on a block device; it invokes mke2fs with ext4 defaults, writes the superblock, inode tables, and journal, and is safe to run on a raw partition. Since /dev/sdb2 is unformatted, this is the direct and correct tool.
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fdisk /dev/sdb2
Why it's wrong here
fdisk is a partition table editor. Running it against a partition such as /dev/sdb2 rather than the whole disk /dev/sdb is unusual, and even on the disk it only creates or deletes partitions. It never writes an ext4 superblock or inode tables, so it cannot produce a usable filesystem here.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official LPI exam blueprint
This LPIC-1 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-1 exam.