APFS

APFS, short for Apple File System, is a proprietary file system developed by Apple Inc. It was announced in 2016 and released with macOS High Sierra in 2017, and it has since become the default file system for Apple devices running macOS, iOS, watchOS, and tvOS that use solid-state storage. It supersedes the older HFS+ design and is optimized for flash and SSD media, offering improved performance, reliability, and space efficiency.

Key features of APFS include copy-on-write metadata, which avoids data corruption by never overwriting live metadata; clones of files and directories that share data until modified; and snapshots that capture the state of the filesystem for backups. It also supports space sharing among volumes in a container, enabling dynamic resizing and efficient use of free space. Other notable capabilities are fast directory sizing, atomic safe-save operations, and native encryption with multi-key support.

APFS volumes may be configured as case-sensitive or case-insensitive; the default is case-insensitive. Encryption modes range from unencrypted to full-disk level encryption with per-volume keys and separate keys for metadata, enabling FileVault-style protection.

In deployment, APFS is implemented as a container that can host multiple volumes; the container manages space across volumes and supports adding or removing volumes without disrupting data. Migration from HFS+ is supported during system upgrades.

APFS has been adopted across Apple platforms to support modern storage technologies, frequent backups, and portability of data across devices.