tune2fs

tune2fs is a command-line utility used to adjust and manage parameters of ext2, ext3, and ext4 filesystems on Unix-like operating systems. It allows users to modify filesystem attributes such as mount options, reserved space, and filesystem labels without needing to reformat the filesystem.

Key Features

• Filesystem Parameter Tuning: Adjust various parameters of ext2/ext3/ext4 filesystems.

• Reserved Space Management: Set aside a portion of the filesystem for the root user to prevent non-root users from filling the disk.

• Filesystem Labeling: Set or change filesystem labels for easier identification.

• Filesystem Check Settings: Configure automatic filesystem checks at boot time.

Basic Usage

The general syntax for tune2fs is:

tune2fs [options] <device>

• [options]: Command-line options for modifying filesystem parameters.

• <device>: The disk partition or device to modify (e.g., /dev/sdX1).

Common Options

• -l: List filesystem parameters.

• -m <percent>: Set the percentage of filesystem space reserved for the root user.

• -L <label>: Set the filesystem label.

• -e <errors>: Set the behavior when filesystem errors are detected (e.g., continue, panic, remount-ro).

• -c <count>: Set the number of mounts between filesystem checks.

• -i <bytes>: Set the number of bytes between inode table checks.

• -o <option>: Set or modify filesystem options (e.g., discard for SSDs).

Examples

List Filesystem Parameters

To list the current parameters of a filesystem on /dev/sda1:

tune2fs -l /dev/sda1

Set Filesystem Label

To set the label of the filesystem on /dev/sda1 to mydata:

tune2fs -L mydata /dev/sda1

Adjust Reserved Space

To set the reserved space percentage to 2% for the root user:

tune2fs -m 2 /dev/sda1

Configure Filesystem Check Interval

To set the filesystem to be checked every 50 mounts:

tune2fs -c 50 /dev/sda1

Configure Filesystem Check Interval by Time

To set the filesystem to be checked every 30 days:

tune2fs -i 30d /dev/sda1

Important Considerations

• Unmount Filesystem: While many options can be applied to a mounted filesystem, it is generally safer to unmount the filesystem before making changes with tune2fs, especially for certain operations.

• Reserved Space: The reserved space is intended to prevent the filesystem from becoming completely full, which helps maintain system performance and prevents potential issues. Adjust the reserved space with care.

• Filesystem Label: Changing the filesystem label can be useful for identifying filesystems, especially in systems with multiple disks or partitions.

Summary

tune2fs is a versatile tool for managing and tuning ext2, ext3, and ext4 filesystems. It allows users to adjust filesystem parameters, manage reserved space, and configure filesystem checks. By using tune2fs, system administrators can optimize filesystem performance, maintain system reliability, and make filesystem management more convenient.