An XFS filesystem on /dev/sdb1 was damaged by a power loss and must be checked and repaired. Which command is the right tool, and what state must the filesystem be in?
LPIC-1 Exam 101-500, objective 104. Devices, Linux filesystems, filesystem hierarchy standard medium
Machine-checked — no person has signed for it. This question was read against the source cited below by an automated pass, which found no contradiction. That is a weaker claim than it sounds: the same kind of process wrote the question, so it can confirm its own mistake.
Treat it as a good draft rather than as settled fact, and read the source below before you rely on it. It is not used in mock exams here — only questions a person has signed for are.
How these questions are written — where each question comes from, what the verification ledger records, and what happens when one is found wrong.
The options
Not correct tune2fs -f /dev/sdb1, with the filesystem mounted
Wrong twice. tune2fs edits ext filesystem parameters, not XFS, and it is not a repair tool in any case.
Not correct xfs_fsr /dev/sdb1, with the filesystem mounted
Wrong. xfs_fsr is the filesystem reorganiser — a defragmenter. It works on mounted filesystems and repairs nothing.
Not correct e2fsck -f /dev/sdb1, with the filesystem unmounted
Wrong. e2fsck understands only ext2/ext3/ext4 superblocks and will refuse or misread an XFS filesystem.
Correct xfs_repair /dev/sdb1, with the filesystem unmounted
Correct. xfs_repair is XFS's checker and it refuses to touch a mounted filesystem. Note that mounting an XFS filesystem normally replays its log; xfs_repair -L discards a dirty log and is a last resort because it loses data.
Why
XFS keeps its own toolset: xfs_repair to check and repair (unmounted only), xfs_fsr to defragment, xfs_db to inspect, xfs_info to report geometry. Running plain `fsck` on XFS does almost nothing — fsck.xfs is essentially a stub that exits successfully so boot scripts do not stall.
Where this comes from
- Cited
- LPI exam objective 104.2
- What it says
- Repair XFS filesystems with xfs_repair; xfs_fsr reorganises rather than repairs.
Practise this
Reading one question is not practice. The trainer will draw a short set from objective 104 and space the ones you get wrong.
More questions on this objective
- A new disk /dev/sdb has no partition table at all. Which command writes an empty GPT partition table onto it without dropping you into an interactive editor? machine-checked
- You need the partition /dev/sdc1 on a USB stick to carry a FAT32 filesystem so that Windows machines can read and write it. Which command creates it? machine-checked
- You have just run `mkswap /dev/sdb2`. Which command makes the kernel start using that swap area immediately, without a reboot? machine-checked
- Why is it dangerous to run e2fsck against an ext4 filesystem that is currently mounted read-write? machine-checked
- On an ext4 filesystem at /dev/sda1 you want an automatic check to be forced after every 30 mounts. Which command sets that? machine-checked
- `df -h /var` reports the filesystem 100% full, but `du -sh /var` accounts for only about half that space. Nothing is hidden under a mount point. What is the most likely explanation? machine-checked
All questions on Devices, Linux filesystems, filesystem hierarchy standard