Administering Local Filesystems and Filesystem Administration

Lesson 1

The `mke2fs` command is used to create and configure an ext2, ext3, or ext4 filesystem in Linux. You can specify the block size of the filesystem using the `-b` option. The block size determines how much data can be stored in a single block on the filesystem.
Here's how you can use `mke2fs` to adjust the block size:
Syntax:

mke2fs -t  -b  /dev/

Example: Suppose you want to create an ext4 filesystem with a block size of 4096 bytes on the `/dev/sdb1` partition. You can use the following command:

mke2fs -t ext4 -b 4096 /dev/sdb1

Supported Block Sizes:

• The allowed block sizes depend on the architecture and filesystem type:
  • 1024 bytes
  • 2048 bytes
  • 4096 bytes
  • 8192 bytes (on some architectures, depending on the page size)

Explanation of Options:

1. -t <filesystem_type>: Specifies the type of filesystem to create (ext2, ext3, or ext4).
2. -b <block_size>: Sets the block size in bytes.
3. /dev/<device>: Specifies the target device or partition for the filesystem.

Notes:

1. Choosing a Block Size: Smaller block sizes are more space-efficient for storing small files, while larger block sizes are better for handling large files.
2. Limitations: Ensure the block size is supported by your kernel and hardware. The block size cannot exceed the system's page size.
3. Filesystem Type: Some features (like journaling in ext3/ext4) and performance characteristics are affected by the block size.

After running the `mke2fs` command, you can verify the block size of the created filesystem using the `dumpe2fs` command:

dumpe2fs /dev/sdb1 | grep "Block size"

Red Hat Linux 9.2 does utilize the automounter for managing file systems. The automounter, specifically the autofs service, is used to mount file systems on demand when they are accessed, which helps in conserving system resources by only mounting directories when they are needed. This functionality is described in various Red Hat documentation sources, confirming that autofs was part of the configuration options in Red Hat Enterprise Linux versions around that time, including Red Hat Linux 9.2.

Filesystems play a pivotal role in your Linux system. Their configuration, performance, and security affect your data's availability and reliability. Properly configured and tuned, your Linux filesystem will provide users with highly available and secure data for years to come. However, if not configured correctly, your filesystems could lose data, become a target of network hackers, or simply not perform optimally.
In this module, you will configure and optimize your Linux filesystems using the ext2fs tools. You will also weigh the advantages of using an automounter^[1] to configure local filesystems against the inherent security risks involved in automounting. Finally, you will learn about tools that monitor and resolve filesystem problems.

• Module Objectives
  After completing this module you will be able to
  1. Use the mke2fs command to adjust the filesystem's block size
  2. Use tune2fs, dumpefs, and debugfs to optimize and configure the ext2 filesystem
  3. Discuss the use of the automounter
  4. Set up the automounter
  5. Use rdist to synchronize files between the local host and a remote machine
  6. Use rsync to synchronize files between the local host and a remote machine
  7. List the commands for monitoring filesystem usage
  8. Resolve filesystem problems

The next lesson discusses optimizing and configuring the ext2 filesystem.

[1]Automounter: An automounter is a program that automatically mounts filesystems when those filesystems are first accessed.