ZFS

Overview

ZFS: the last word in file systems - at least according to Sun Microsystems back in 2004. But it’s pretty much true for traditional file servers. You add disks to a pool where you decide how much redundancy you want, then create file systems that sit on top. ZFS directly manages it all. No labeling, partitioning or formatting required.

There is error detection and correction, zero-space clones and snapshots, compression and deduplication, and delta-based replication for backup. It’s also highly resistent to corruption from power loss and crashes because it uses Copy-On-Write.

This last feature means that as files are changed, only the changed-bits are written out, and then the metadata updated at the end as a separate and final step to include these changed bits. The original file stays the same until the very end. An interruption in the middle of a write (such as from a crash) leaves the file undamaged.

Lastly, everything is checksummed and automatically repaired should you ever suffer from silent corruption.