Filesystems in Depth is a practical engineering guide to how storage systems actually work — from the block-and-inode model every Unix filesystem inherits, through modern extent trees, journaling, and copy-on-write, to the distributed and object-storage systems that underpin modern infrastructure. It covers ext4, XFS, Btrfs, and ZFS in depth, then moves outward to NFS, CephFS, and S3-compatible object storage. Along the way it addresses the failure modes that quietly destroy data — journals disabled for performance, extent trees fragmented under load, inode tables exhausted, snapshots that grow unbounded, silent bit rot that no scrub can repair, storage firmware that lies about completed writes — each with the countermeasure and the operational tradeoff.
