EX200 Create and configure file systems Practice Question
A Red Hat Enterprise Linux system has a second disk /dev/sdb with a single partition /dev/sdb1 that was formatted as XFS and mounted at /mnt/backup. The administrator wants to change the filesystem on /dev/sdb1 to ext4 without losing existing data. Which steps should be taken in order?
⚠ Common exam trap
Candidates often assume a filesystem can be 'converted' in place using a command like fsck or a tuning tool, when in fact only a backup-and-restore cycle is safe for changing between fundamentally different filesystem types like XFS and 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
✓
Backup data, unmount, mkfs.ext4, remount, restore data
You cannot convert an XFS filesystem to ext4 in place; the only safe method is to back up the data, unmount the partition, create a new ext4 filesystem with mkfs.ext4, remount, and then restore the data. XFS and ext4 have fundamentally different on-disk structures (e.g., allocation groups vs. block groups, different journaling formats), so no in-place conversion tool exists.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Unmount, mkfs.ext4 /dev/sdb1, then mount
Why it's wrong here
Unmounting the partition only ensures no filesystem is active, but running mkfs.ext4 on /dev/sdb1 initializes a brand-new ext4 filesystem by writing a fresh superblock and metadata over the entire partition, irrecoverably overwriting any existing XFS or other data stored there. Without a preliminary backup and a subsequent restore step, this process destroys all files and directories on the disk, so it does not satisfy the requirement to preserve data.
- ✗
Use xfs_admin to change type
Why it's wrong here
xfs_admin is a management utility for tuning XFS-specific parameters such as the filesystem label, UUID, or inode size; it reads and writes only the XFS superblock and has no concept of ext4's on-disk format. Invoking it cannot change the filesystem type from XFS to ext4 because no tool can alter the fundamental filesystem format in place, and xfs_admin would simply report an error or require an existing XFS filesystem to operate on.
- ✗
Use fsck.ext4 to convert in place
Why it's wrong here
fsck.ext4 is intended exclusively for checking and repairing existing ext2, ext3, or ext4 filesystems by validating and fixing inconsistencies in their metadata. It cannot read the XFS superblock, journal, or allocation groups on /dev/sdb1, so it is incapable of converting an XFS filesystem to ext4; running it may misidentify the data or fail because the on-disk structures do not match what the ext4 checker expects.
- ✓
Backup data, unmount, mkfs.ext4, remount, restore data
Why this is correct
The correct procedure is to first copy all data from /dev/sdb1 to a safe location (e.g., tar, rsync, or cp to another disk), then unmount the partition, run mkfs.ext4 /dev/sdb1 to create a new ext4 filesystem, remount the partition, and finally restore the data from the backup. This sequence preserves user files and directory structure because the destructive mkfs operation is performed only after a verified backup exists, and the restore repopulates the freshly formatted ext4 filesystem with the original content.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This EX200 practice question is part of Courseiva's free Red Hat 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 EX200 exam.