LFCS Storage Management Practice Question

A storage administrator notices that a newly created XFS filesystem on a logical volume shows only 90% of the expected capacity. The logical volume is 100GB. What is the most likely cause?

⚠ Common exam trap

Candidates often confuse the 10% XFS reserved blocks with filesystem overhead from journaling (ext4) or assume it is a bug, when in fact it is a configurable default behavior of `mkfs.xfs`.

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

✓

The filesystem was created with a reduced size due to mkfs.xfs default settings.

B is correct because `mkfs.xfs` by default reserves 10% of the filesystem space for metadata and performance optimization (the `-i maxpct` and internal log overhead). This is not a capacity loss but a design feature of XFS, which explains why a 100GB logical volume shows only ~90GB usable.

Answer analysis

Option-by-option breakdown

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

✗
The disk has bad blocks that were marked as unusable.
Why it's wrong here
Bad blocks are not typically the cause of a consistent 10% reduction.
✓
The filesystem was created with a reduced size due to mkfs.xfs default settings.
Why this is correct
XFS reserves space for metadata; mkfs.xfs may not use full device if size is not specified.
✗
The volume group has insufficient physical extents.
Why it's wrong here
The logical volume was created successfully, so VG has enough extents.
✗
The filesystem is mounted with the 'noatime' option.
Why it's wrong here
Mount options do not affect capacity.

Go deeper

LFCS Storage Management Practice Question

Why each option matters

Option-by-option breakdown

Related to this question