Apple’s new filesystem, simply called “Apple File System” (APFS), will soon be the replacement for the for Mac OS Extended (HFS+) filesystem which was first introduced in Mac OS 8.1 back in 1998. It’s main focus is encryption and is optimized for flash and SSD storage devices. It’s also designed for scalability and will run on everything from the Apple Watch to the Mac Pro.
APFS is a much needed new filesystem with an impressive list of modern new features:
Clones - allows copying of the same file without taking up additional storage space
Snapshots - a read-only version of your file system at a particular time
Encryption - single-key or multi-key encryption for greater security
64-bit inode numbers - allows more files on a single volume and greater security
Metadata checksums - provides better data integrity in case of crashes
Containers - volumes built using a single or multiple partitions which allow space sharing
All of these new features will bring a faster, more secure, and more stable underlying filesystem for all Apple devices. It actually gives more storage on devices as it’s able to more accurately calculate and use data than the older HFS+ filesystem could previously. Snapshots, for example, is a really impressive feature that could replace Time Machine as it’s a much more efficient way to make backups of an entire system at a certain point in time. The clones feature will also significantly speed up file transfers and copying. A user report states that making a copy of the iTunes installer on a volume using APFS was almost instant, whereas it took 17 seconds on a volume using the older HFS+ filesystem.
If you’re using iOS 10.3 or higher on your iPhone or iPad you're already using this new filesystem, and it will be the default filesystem for computers when macOS High Sierra comes out this fall. You can try out a beta version of APFS now using Sierra or with the High Sierra public beta using the diskutil command in Terminal. If you decide to try APFS be sure to have a backup of your data, as this is still beta software and stability is not guaranteed. Also, due to it still being beta, it doesn’t yet support compression, Time Machine, FileVault, Fusion drives, or RAID arrays. These limitations should be worked out by the final release of High Sierra later this year.