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News and tips from the experts at Carbon Copy Cloner

All articles with the category APFS Clear

An analysis of APFS enumeration performance on rotational hard drives


My APFS-formatted rotational disks have always felt slower than when they were HFS+ formatted. The speed of copying files to them felt about the same, but slogging through folders in the Finder was taking a lot longer. At first I shrugged it off to the filesystem being new; "It just needs some tuning, it will come along." But that performance hasn't come along, and after running some tests and collecting a lot more data, I'm convinced that Apple made a fundamental design choice in APFS that makes its performance worse than HFS+ on rotational disks. Performance starts out at a significant deficit to HFS+ (OS X Extended) and declines linearly as you add files to the volume.

The rest of this article is fairly technical, here are the key takeaways:

  • Enumerating an APFS filesystem on a traditional HDD (rotational disk) will take 3-20X longer than HFS+ on the same hardware.
  • This performance difference is most noticeable on a macOS startup disk that is (or includes) a rotational disk.
  • If Apple doesn't make some concessions in the APFS filesystem to accommodate the slower seek performance of HDD devices, then a rotational device will never be able to provide acceptable...

Building Better Backups with Carbon Copy Cloner

Watch a video of this tutorial on YouTube

Note: This will erase all data on your backup disk!!!

Launch Disk Utility

Open a Finder window and navigate to Applications > Utilities and double click on Disk Utility.

Launch Disk Utility

The remaining steps vary considerably depending on the operating system you are running. Choose About This Mac from the Apple menu to determine your current OS, then make a selection below.

Instructions for Sierra and El Capitan

Select the backup disk

Click to select the disk that you would like to use for your backup. This disk should not be the same as your startup disk.

The name of a new disk will often include the manufacturer’s name (e.g. WD My Book 111D Media...). A startup disk will often include the manufacturer's serial number in the title (e.g. TOSHIBA MK50...).

Select the backup disk

Erase the backup disk

Click on the Erase button in Disk Utility's toolbar, then configure the...