tune2fs command allows you to view and change various filesystem parameters on Linux ext2, ext3, or ext4 filesystems. Some parameters you can modify are filesystem volume name, maximum mount count, mount count, interval time between two filesystem checks, last checked time, etc.
tune2fs can also convert an ext2 filesystem to an ext3 filesystem and an ext3 filesystem to an ext4 filesystem.
How to use tune2fs command
The syntax for using the tune2fs command is as follows:
tune2fs [options] device
You will need the sudo privileges to run the tune2fs command in Linux.
Common Options:
-c max-mount-counts: Adjust the number of mounts after which the filesystem will be checked bye2fsck.-e error-behavior: Change the behavior of the kernel code when errors are detected (continue,remount-ro, orpanic).-g group: Change the group of the filesystem.-i interval-between-checks[d|m|w]: Adjust the maximum time between filesystem checks.-j: Add an ext3 journal to the filesystem.-l: List the contents of the superblock.-L volume-label: Set the volume label of the filesystem.-m reserved-blocks-percentage: Set the percentage of the filesystem that will be reserved for the super-user.-M last-mounted-directory: Set the last-mounted directory for the filesystem.-o [^]mount-option[,...]: Adjust the default mount options.-r reserved-blocks-count: Set the number of reserved blocks.-s sparse_super: Set or clear the sparse super feature flag.-U UUID: Set the universally unique identifier (UUID) of the filesystem.-C mount-count: Set the number of times the filesystem has been mounted.-E extended-option[,...]: Set extended options for the filesystem.-f: Force the tune2fs operation.-T time-last-checked: Set the time when the filesystem was last checked.
1. List the contents of the filesystem
The tune2fs command with -l option displays the current filesystem parameters.
$ sudo tune2fs -l device
Sample Output:
2. Display filesystem volume label
You can use the tune2fs command with grep command to get only the volume name of a filesystem.
$ sudo tune2fs -l device | grep volume
Sample Output:
golinux@ubuntu-PC:~$ sudo tune2fs -l /dev/sda5 | grep volume
Filesystem volume name: <none>
As you can see, there is no volume label for /dev/sda5.
3. Set the filesystem volume name
The -L option sets the volume label of the filesystem.
$ sudo tune2fs -L volume_name device
Sample Output:
The following example sets the volume label golinux for /dev/sda5.
4. View mount count and maximum mount count
You can view the filesystem's mount count and maximum count by grepping the pattern "mount count".
$ sudo tune2fs -l /dev/sda5 | grep -i "mount count"
Sample Output:
golinux@ubuntu-PC:~$ sudo tune2fs -l /dev/sda5 | grep -i "mount count"
Mount count: 79
Maximum mount count: -1
5. Change the maximum mount count of a filesystem
The -c option sets the maximum number of mounts, after which e2fsck should check the filesystem.
The following example changes the maximum count of /dev/sda5 to 30.
$ sudo tune2fs -c 30 /dev/sda5
Sample Output:
6. Change the mount count of a filesystem
You can change the mount count of a filesystem using the -C option. It indicates the number of times the filesystem has been mounted.
This command sets the mount count of /dev/sda5 to 100.
$ sudo tune2fs -C 100 /dev/sda5
Sample Output:
7. Display Check Interval of a filesystem
You can view the Check Interval value of a filesystem by searching the pattern "interval" with the grep command.
$ sudo tune2fs -l /dev/sda5 | grep interval
Output:
golinux@ubuntu-PC:~$ sudo tune2fs -l /dev/sda5 | grep interval
Check interval: 0 (<none>)
The value is zero as of now.
8. Set the intervals between two filesystem checks
The -i option allows you to set the maximal time between two filesystem checks.
$ sudo tune2fs -i interval [d|m|w]
- d=days
- w=weeks
- m=months
The following command enables filesystem checks every 2 weeks on /dev/sda5.
$ sudo tune2fs -i 2w /dev/sda5
Sample Output:
9. Disable filesystem check on boot
You can set the Maximum mount count and Check interval value to -1 to disable filesystem check on boot in Linux.
The following commands disable filesystem checks on boot for /dev/sda5.
$ sudo tune2fs -c -1 /dev/sda5
$ sudo tune2fs -i -1 /dev/sda5
Sample Output:
10. Set the last-mounted directory
To set the last-mounted directory for the filesystem, use the tune2fs command with -M option.
$ sudo tune2fs -M mount_dir /dev/sda5
Sample Output:
11. Set the last time checked of a filesystem
You can set the last checked time of a filesystem using the -T option. The time format should be the international date format, i.e. YYYYMMDD[HH[MM[SS]]].
The keyword now can be used to set the current time.
$ sudo tune2fs -T now /dev/sda5
Sample Output:
golinux@ubuntu-PC:~$ sudo tune2fs -T now /dev/sda5
tune2fs 1.45.5 (07-Jan-2020)
Setting time filesystem last checked to Sat Aug 13 23:36:54 2022
12. Change the error behavior of a filesystem
You can use the -e option to change the behavior of the kernel code when errors are detected. The accepted values are:
- continue: continue normal execution
- remount-ro: remount filesystem to read-only
- panic: cause a kernel panic
The following command sets the error behavior of /dev/sda5 to continue.
$ sudo tune2fs -e continue /dev/sda5
Sample Output:
golinux@ubuntu-PC:~$ sudo tune2fs -e continue /dev/sda5
tune2fs 1.45.5 (07-Jan-2020)
Setting error behavior to 1
13. Converting ext File System to an ext3
The -j option can add an ext3 journal to an ext2 filesystem without altering the data on the partition.
The following command converts the filesystem /dev/sda2 from ext2 to an ext3.
$ sudo tune2fs -j /dev/sda5
Note: Back up your data before running this command as it might cause corruption of the filesystem and data loss.
14. Change the UUID of the filesystem
The UUID of the filesystem is a series of hexadecimal digits separated by hyphens that looks like this: 5b146274-db93-4c42-86ab-80c1580585c7.
You can set the universally unique identifier (UUID) of the filesystem using the -U option.
$ sudo tune2fs -U UUID /dev/sda5
Other accepted parameters are:
- clear: clear the UUID of the filesystem
- random: generate a new random UUID
- time: generate a time-based UUID
The following command sets a new randomly-generated UUID for the filesystem /dev/sda5.
$ sudo tune2fs -U random /dev/sda5
The UUID can only be changed when the filesystem is unmounted.
15. Set the filesystem feature in the filesystem
You can set or clear the feature in the filesystem using the -O option. Multiple features can be specified by separating them with commas.
The following command adds the indicated features to an ext3 filesystem /dev/sda5 and converts it to an ext4 filesystem.
$ sudo tune2fs -O extents,uninit_bg,dir_index /dev/sda5
To clear the features, you need to specify filesystem features with a caret character ^ at the beginning.
$ sudo tune2fs -O ^extents,^uninit_bg,^dir_index /dev/sda5
Conclusion
Now you know how to view and change filesystem parameters using the tune2fs command. tune2fs is a handy tool in Linux for adjusting various filesystem parameters on ext2, ext3, or ext4 filesystems. If you have any confusion, let us know in the comment section.
What's Next
How to create filesystem on a Linux partition or logical volume
Steps to repair filesystem in rescue mode in RHEL/CentOS 7/8 Linux
Further Reading
