LFCS Storage Management Practice Question
A Linux server has a single XFS filesystem mounted at /data on /dev/sdb1. The storage array behind /dev/sdb1 is expanded and the block device is now 2 TB instead of 1 TB. The administrator confirms that the kernel sees the larger device with blockdev --getsize64 /dev/sdb1. Which command should be run to make the additional space usable by the mounted /data filesystem?
⚠ Common exam trap
The trap here is assuming that any resize utility works on any filesystem, when XFS must be grown with xfs_growfs on the mount point rather than resize2fs on the device.
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
✓
xfs_growfs /data
XFS filesystems are extended with the xfs_growfs command, which operates on a mounted filesystem using its mount point. Because the block device already reports the larger size, the only remaining step is to grow the XFS filesystem into that free space. Tools such as resize2fs target ext-family filesystems, while xfs_repair and growpart address different problems, so they cannot satisfy this requirement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
xfs_growfs /data
Why this is correct
xfs_growfs is the correct tool for expanding a mounted XFS filesystem. It takes the mount point as its argument, not the block device, and it communicates with the running XFS kernel module to extend the filesystem into the additional space that the underlying block device now exposes. Running it on /data grows the live filesystem without unmounting it, which is exactly what this scenario requires.
- ✗
growpart /dev/sdb 1
Why it's wrong here
growpart modifies a partition table entry to make a partition consume more of its parent disk. In this scenario the administrator has already confirmed that the kernel sees the block device /dev/sdb1 as 2 TB, meaning the partition (or whole-disk device) already reflects the new size. growpart would not extend the XFS filesystem itself and would be at best a redundant step, leaving /data still at its old size.
- ✗
resize2fs /dev/sdb1
Why it's wrong here
resize2fs is designed for ext2, ext3, and ext4 filesystems, not XFS. If it is pointed at an XFS block device it will fail with an error about a bad magic number or unsupported filesystem. Even though resize2fs can grow mounted ext4 filesystems online, it has no code path for XFS metadata, so it cannot help here and may confuse an administrator into thinking the device is corrupt.
- ✗
xfs_repair /dev/sdb1
Why it's wrong here
xfs_repair is a consistency-checking and repair utility for XFS. It is used when a filesystem is damaged or was not cleanly unmounted, and it normally requires the filesystem to be unmounted. It does not resize or extend a filesystem, and running it on a healthy mounted filesystem will typically refuse to proceed or could cause unnecessary risk. It is not the right tool for adding capacity.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Linux Foundation exam blueprint
This LFCS practice question is part of Courseiva's free Linux Foundation 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 LFCS exam.