Enlarge / We’re not saying that APFS snapshots will be used in a future revision of Time Machine, but if you’re a betting person, now might be a good time to place your bets. (credit: Aurich / Thinkstock)

Back in June, Apple announced its new upcoming file system: APFS, or Apple File System. There was no mention of it in the WWDC keynote, but devotees needed no encouragement. They picked over every scintilla of data from the documentation on Apple’s developer site, extrapolating, interpolating, eager for whatever was about to come. In the WWDC session hall, the crowd buzzed with a nervous energy, eager for the grand unveiling of APFS. I myself badge-swapped my way into the conference just to get that first glimpse of Apple’s first original filesystem in the 30+ years since HFS.

Apple’s presentation didn’t disappoint the hungry crowd. We hoped for a modern filesystem, optimized for next generation hardware, rich with features that have become the norm for data centers and professionals. With APFS, Apple showed a path to meeting those expectations. Dominic Giampaolo and Eric Tamura, leaders of the APFS team, shared performance optimizations, data integrity design, volume management, efficient storage of copied data, and snapshots—arguably the feature of APFS most directly in the user’s control.

Far from vaporware, Apple made APFS available to registered developers that day. The company included it in macOS Sierra as a technology preview. You can play with APFS today and a lot of the features are there. You can use space sharing to carve up a single disk into multiple volumes. You can see the speed of its directory size calculation—nearly instantaneous—compared with the slow process on HFS+. You can use clones to make constant-time copies of files or directories. At WWDC, Apple demonstrated the feature folks were the most eager to play with: snapshots. Tamura used snapshotUtil to create, list, and mount snapshots. But early adopters quickly discovered that snapshotUtil wasn’t part of the APFS technology preview.