My understanding is that with APFS, volumes exist inside containers, and the volumes all grow as much as needed, as long as there is space in the container.

But I want to limit the space for the volumes. I have a 2TB disk with two volumes - one for Time Machine and one for general storage. I don't want the Time Machine volume to take the entire physical disk. Sadly, there is no way (in macOS 11 Big Sur) to delete Time Machine snapshots, so I need to limit its space by limiting the size of the volume.


When creating an APFS volume, you can set a quota. In Disk Utility, in the sheet to create a new volume, choose Size Options and set a Quota Size.

The optional quota size limits how much storage this volume can allocate.

This can't be added or changed for an existing volume.

  • 1
    Wow, that's weird that you can set or change it. Well, I created a new volume, and set the quota. Now I will point Time Machine at the new one, and delete the old one. – Rob N Dec 16 '20 at 23:32
  • @RobN Did that work - as after setting the quota Setting Time Machine to there undoes the quota – mmmmmm Jan 13 at 20:33
  • No, it didn't work. As you said, Time Machine removed the quota. – Rob N Jan 14 at 21:34

There is no way to limit individual APFS volumes that are used with Time Machine as per macOS 11.1. Any quota pre-set to an APFS volume would be removed by Time Machine when it takes over it.

The only way would be to partition the drive and create distinct APFS containers to limit Time Machine's use of the drive.

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