Checking and Repairing an Ext File System

Use the fsck utility to check and repair file systems.

For file systems other than root (/) and /boot, mount invokes file system checking if more than a specified number of mounts have occurred or more than 180 days have elapsed without checking having being performed. You can run fsck manually if a file system hasn't been checked for several months.

For more information, see the fsck(8) manual page.

The following procedure describes how to check and repair an Ext file system.

Attention:

Running fsck on a mounted file system can corrupt the file system and cause data loss.

Unmount the file system:
```
sudo umount filesystem
```
Use the fsck command to check the file system:
```
sudo fsck [-y] file-system
```
The file-system specifies a device name, a mount point, a label, or UUID specifier, for example:
```
sudo fsck UUID=ad8113d7-b279-4da8-b6e4-cfba045f66ff
```
By default, the fsck command prompts you to confirm whether to apply a suggested repair to the file system. If you specify the -y option, the command assumes a yes response to all such questions.

For the ext3, and ext4 file system types, other commands that are used to perform file system maintenance include dumpe2fs and debugfs. dumpe2fs prints super block and block group information for the file system on a specified device. debugfs is an interactive file system debugger that requires expert knowledge of the file system architecture.