Filesystem

A filesystem is the logical layer that maps raw blocks on storage hardware to a structured hierarchy of files and directories.

Modern filesystems like ZFS, XFS, and ext4 act as the critical interface between hardware and data. They manage metadata (inodes), handle space allocation through extents, and ensure data integrity via journaling or copy-on-write (CoW) mechanisms. By abstracting physical sectors into a readable tree structure, these systems provide essential features such as POSIX compliance, snapshots, and transparent compression. Whether you are scaling a petabyte-scale Lustre cluster or managing a local NVMe drive, the filesystem dictates the performance ceiling and reliability of your entire I/O stack.

https://www.kernel.org/doc/html/latest/filesystems/index.html