What Filesystem Does Ubuntu Use by Default?

When you perform a fresh installation of Ubuntu, the installer automatically selects the ext4 (Fourth Extended Filesystem) as the default filesystem for your storage drive. This article explores why Ubuntu uses ext4, its key features, and the alternative filesystem options available during the setup process.

Why Ubuntu Defaults to ext4

The ext4 filesystem has been the standard choice for Ubuntu and many other major Linux distributions for years. It is highly regarded for its exceptional stability, performance, and backward compatibility with older ext2 and ext3 systems. Because it has been rigorously tested in both consumer and enterprise environments, it provides a reliable foundation for everyday OS operations.

Key Features of the ext4 Filesystem

• Journaling: ext4 keeps a journal of changes that are about to be made to the storage drive. If your system suffers a sudden power loss or crashes, the journal allows the filesystem to recover quickly without corrupting your data.
• Large File and Volume Support: It can support individual file sizes up to 16 terabytes (TB) and total volume sizes up to 1 exabyte (EB), making it more than capable of handling modern storage demands.
• Delayed Allocation: Instead of writing data to the disk immediately, ext4 blocks are allocated only when the data is about to be written. This improves performance and reduces file fragmentation.

Alternative Filesystems in the Ubuntu Installer

While ext4 is the automated choice, the Ubuntu advanced installation menu allows users to select other filesystems depending on their specific technical needs:

• ZFS: Offered as an experimental option in the installer, ZFS combines a filesystem with a logical volume manager. It is praised for its data integrity features, automated snapshots, and built-in drive pooling, though it consumes more system memory.
• Btrfs: A modern copy-on-write (CoW) filesystem designed for fault tolerance, easy repair, and simplified administration. It supports snapshots and drive pooling natively.
• XFS: A highly scalable, high-performance filesystem that excels at handling large files and parallel input/output operations, making it popular in server environments.