Given their very different structure, backups on APFS disks shouldn’t require routine maintenance. Checking and repair is performed using Disk Utility.
APFS is almost 4 years old, and set out to solve the problem of accumulation of minor errors which has plagued HFS+. Has it?
Although generally reliable in normal macOS and in Recovery, First Aid sometimes runs into problems with external bootable disks.
There’s no more critical app on your Mac, yet Disk Utility has suffered years of neglect – years in which APFS has grown many new features, and all Disk Utility gets is bugs and workaround.
Disk Utility in Big Sur can turn a 1 TB external disk into 4.5 TB or more of imaginary containers. Sadly it’s just a bug, and here’s how to work around it.
We don’t know when Apple decided to introduce Big Sur’s SSV, but even now it hasn’t told users it won’t be releasing standalone updates for 11.0.1 or 11.1.
For many, this could be the best reason for upgrading early. Even when it doesn’t go quite as expected, this really isn’t difficult.
Volume layouts are fairly straightforward until you have two or more bootable systems with Volume Groups. Details and advice for those with macOS 10.15 or 11.
Disk structure diagrammed for comparison, from the partition table, to HFS+ and APFS volumes, with further references.
What you need to know about the APFS file system, its containers and volumes, so you can understand errors and how to repair them.