Block Devices, Filesystems and Advanced Storage →easyMultiple ChoiceObjective-mapped

LPIC-2 Practice Question: Block Devices, Filesystems and Advanced Storage

An administrator needs to create an ext4 filesystem on /dev/sdb1 with a block size of 4096 bytes and reserve 2% of blocks for root. Which command accomplishes this?

⚠ Common exam trap

It's easy for candidates to confuse the `-b` (block size) and `-m` (reserved blocks percentage) flags with similar-looking but incorrect flags like `-B` or `-M`, or mistakenly use long options like `--block-size` without verifying the exact syntax supported by mkfs.ext4.

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 -b 4096 -m 2 /dev/sdb1

Mkfs.ext4 uses the `-b` option to specify the block size in bytes (4096) and `-m` to set the reserved blocks percentage for root (2%). The `-b` flag is the standard short form for block size in the mke2fs family of tools, and `-m` accepts a percentage value directly.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
mkfs.ext4 --block-size 4096 -m 2 /dev/sdb1
Why it's wrong here
The flag for block size is -b, not --block-size.
✗
mkfs.ext4 -B 4096 -m 2 /dev/sdb1
Why it's wrong here
-B is not a valid flag for mkfs.ext4; block size is set with -b.
✓
mkfs.ext4 -b 4096 -m 2 /dev/sdb1
Why this is correct
-b sets block size to 4096 bytes; -m sets reserved percentage to 2.
✗
mkfs.ext4 -b 4096 -M 2 /dev/sdb1
Why it's wrong here
-M is invalid; use -m for reserved blocks percentage.

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LPIC-2 Practice Question: Block Devices, Filesystems and Advanced Storage

Why each option matters

Option-by-option breakdown

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