The APFS File System
Fergus Toolan · 2025
All modern Apple devices use the Apple File System (APFS) by default. This is a modern B-Tree based file system that provides many advanced capabilities. APFS permits the file system to contain multiple independent volumes which share space in the APFS container. As APFS uses copy-on-write (CoW) for updating metadata it also provides the possibility to recover older versions of data from the file system. Related to CoW, APFS automatically creates checkpoints which can be used to recover older versions of the file system.