File system types (ext4, xfs) in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Identify the file system type of a mounted partition

You run the command df -T /home on a Linux system. What is the expected output format for the file system type column?

Linux CLI

df -T /home

A Shows the file system size in the second column

B Shows the mount point path in the second column

C Shows the file system type like ext4 or xfs in the second column

D Shows the disk usage percentage in the second column

💡 Hint

The -T option in df shows the file system type.

The df -T command lists disk space usage and includes the file system type in the second column, such as ext4 or xfs.

🧠 Conceptual

intermediate

Difference between ext4 and xfs file systems

Which statement correctly describes a key difference between ext4 and xfs file systems?

A xfs is optimized for large files and parallel I/O, ext4 is more general-purpose

B ext4 supports journaling, but xfs does not

C ext4 cannot be resized while mounted, xfs can be resized online

D xfs is the default file system for all Linux distributions

💡 Hint

Think about performance and typical use cases for each file system.

xfs is designed for high-performance with large files and parallel I/O workloads, while ext4 is a versatile, general-purpose file system.

🔧 Debug

advanced

Fix the error when creating an xfs file system

You run mkfs.xfs /dev/sdb1 but get an error: Device or resource busy. What is the most likely cause?

A The partition is formatted with ext4 already

B The partition /dev/sdb1 is currently mounted

C The device /dev/sdb1 does not exist

D The xfs tools are not installed

💡 Hint

Check if the device is in use before formatting.

You cannot format a partition that is currently mounted. Unmount it first to avoid the 'Device or resource busy' error.

🚀 Application

advanced

Mount an ext4 file system with specific options

You want to mount an ext4 partition at /mnt/data with read-only access and no execution of binaries. Which mount command is correct?

A mount -o ro,noexec /dev/sdc1 /mnt/data

B mount -t ext4 -o rw,exec /dev/sdc1 /mnt/data

C mount -t xfs -o ro,noexec /dev/sdc1 /mnt/data

D mount -t ext4 -o ro,noexec /dev/sdc1 /mnt/data

💡 Hint

Specify the file system type and options explicitly.

Option D correctly specifies ext4 file system type with read-only and no execution options.

💻 Command Output

expert

Output of xfs_info command on an xfs partition

What kind of information does the xfs_info /dev/sdd1 command provide?

A Detailed metadata about the xfs file system including block size and inode size

B Current disk usage statistics like free and used space

C List of files and directories on the partition

D Partition table layout of the disk

💡 Hint

Think about file system structure details, not usage or file listing.

xfs_info shows metadata details such as block size, inode size, and allocation groups of the xfs file system.

Practice

1. Which command is used to create an ext4 file system on a disk partition?

easy

A. format /dev/sdX1

B. mkfs.xfs /dev/sdX1

C. mkfs.ext4 /dev/sdX1

D. diskformat ext4 /dev/sdX1

Solution

1. Step 1: Understand the command for ext4 file system creation

   The command mkfs.ext4 is specifically designed to create ext4 file systems on a given partition.

2. Step 2: Identify the correct usage with device name

   Using mkfs.ext4 /dev/sdX1 formats the partition /dev/sdX1 as ext4.

3. Final Answer:

   mkfs.ext4 /dev/sdX1 -> Option C

4. Quick Check:

   ext4 creation command = mkfs.ext4 [OK]

Hint: ext4 uses mkfs.ext4 command to format partitions [OK]

Common Mistakes:

• Confusing mkfs.xfs with mkfs.ext4
• Using generic format commands not valid in Linux
• Trying to use unsupported commands like diskformat

2. Which of the following is the correct syntax to create an XFS file system on /dev/sdb1?

easy

A. mkfs.ext4 /dev/sdb1

B. mkfs.xfs /dev/sdb1

C. mkfs.xfs -t xfs /dev/sdb1

D. format xfs /dev/sdb1

Solution

1. Step 1: Identify the command for XFS file system creation

   The command mkfs.xfs is the standard way to create an XFS file system on a partition.

2. Step 2: Confirm the correct device usage

   Using mkfs.xfs /dev/sdb1 formats the partition /dev/sdb1 as XFS.

3. Final Answer:

   mkfs.xfs /dev/sdb1 -> Option B

4. Quick Check:

   XFS creation command = mkfs.xfs [OK]

Hint: Use mkfs.xfs for XFS file system creation [OK]

Common Mistakes:

• Using mkfs.ext4 instead of mkfs.xfs
• Trying mkfs.xfs -t xfs which is invalid syntax
• Using Windows-like format commands

3. What will be the output of the command file -s /dev/sdc1 after formatting /dev/sdc1 with ext4?

medium

A. /dev/sdc1: Linux rev 1.0 ext4 filesystem data

B. /dev/sdc1: XFS filesystem data

C. /dev/sdc1: data

D. /dev/sdc1: DOS/MBR boot sector

Solution

1. Step 1: Understand the file command with -s option

   The file -s command reads the device or file to identify its type.

2. Step 2: Recognize the output for ext4 formatted partition

   After formatting with ext4, the output shows Linux rev 1.0 ext4 filesystem data indicating ext4 file system.

3. Final Answer:

   /dev/sdc1: Linux rev 1.0 ext4 filesystem data -> Option A

4. Quick Check:

   file -s on ext4 = ext4 filesystem data [OK]

Hint: file -s shows filesystem type on device [OK]

Common Mistakes:

• Expecting XFS output after ext4 format
• Confusing raw data output with filesystem info
• Assuming DOS/MBR boot sector output on formatted partition

4. You ran mkfs.ext4 /dev/sdd1 but got an error: "device is mounted". What is the best fix?

medium

A. Unmount the device using umount /dev/sdd1 and retry

B. Use mkfs.xfs instead of ext4

C. Reboot the system and run the command again

D. Format a different device without unmounting

Solution

1. Step 1: Understand the error cause

   The error "device is mounted" means the partition is currently in use and cannot be formatted.

2. Step 2: Unmount the device before formatting

   Using umount /dev/sdd1 frees the device so mkfs.ext4 can run successfully.

3. Final Answer:

   Unmount the device using umount /dev/sdd1 and retry -> Option A

4. Quick Check:

   Unmount device before formatting = umount [OK]

Hint: Unmount device before formatting to avoid errors [OK]

Common Mistakes:

• Trying different filesystem without unmounting
• Rebooting unnecessarily instead of unmounting
• Ignoring the mounted status and forcing format

5. You need a file system for a large data server that requires fast write speed and supports files larger than 16TB. Which file system should you choose?

hard

A. ext4

B. NTFS

C. FAT32

D. XFS

Solution

1. Step 1: Analyze file system limits and performance

   ext4 supports large files but has a practical limit around 16TB; XFS supports very large files and is optimized for high-speed writes.

2. Step 2: Match requirements to file system features

   XFS is designed for large data servers with fast write speeds and supports files larger than 16TB, making it the best choice.

3. Final Answer:

   XFS -> Option D

4. Quick Check:

   Large fast files = XFS [OK]

Hint: Choose XFS for large files and fast writes on servers [OK]

Common Mistakes:

• Choosing ext4 without checking file size limits
• Selecting FAT32 which has small file size limits
• Confusing NTFS as a Linux-native file system