APFS, though, was much slower to start with, and got progressively worse, regardless of whether defragmentation was enabled, and largely irrespective of snapshots. The time taken to enumerate the million files was consistently shortest (best performance) on HFS+, and changed little there over twenty repetitions of the test. In case a million files seems excessive, with files nested three folders deep, this is only 111,000 folders, and a maximum file size of 20 GB – hardly excessive by real world standards. He enumerated a million files in the file system on a hard disk over a period of simulated modifications to the file system, under both HFS+ and APFS. Take a freshly-formatted hard disk and run normal benchmarks on it, and you’ll probably find little difference between the two file systems.Ī little while ago, though, Mike Bombich, developer of Carbon Copy Cloner, came up with a much better way of comparing performance. It has been quite difficult to demonstrate relative performance between HFS+ and APFS on hard drives, as conventional disk benchmarking doesn’t produce a standard degree of fragmentation for the purposes of comparison. The end result is that file system metadata in APFS get hopelessly fragmented, which in turn causes performance problems on hard drives. It’s essential for the file system metadata, as there’s no journalling, which has proved a saving grace in HFS+. In APFS, one of its most important features, copy on write, is almost designed to cause fragmentation.

In HFS+, the solution has been to defragment the used and free space on the disk, something which macOS does to a degree, and several third-party tools have long supported. For an SSD, fragmentation of the file system metadata and file data has no cost, but for hard disks it can kill performance, as each attempt to access data on the disk turns into a long series of seeks to find all the blocks required.

APFS was designed primarily for SSDs, and has quite a major problem when used with traditional rotating hard disks: fragmentation. But backups made using other software, and simple file repositories, could be in either HFS+ or APFS.Ĭhoosing which to use can be difficult. If you’re using your hard drive(s) for Time Machine backups, then you have no option as to their format, as those backups must go onto HFS+ volumes. For bulk storage of more than a terabyte of files, they’re still the only affordable option for most users. Like it or not, many of us are still using hard drives after we’ve upgraded to High Sierra or later.

Defrag mac drive