3 ms·

APFS has a nice feature in that it can share free space between different volumes on the same physical device. So, for example, I can have a Time Machine backup

APFS has a nice feature in that it can share free space between different volumes on the same physical device. So, for example, I can have a Time Machine backup and a general-purpose volume on my external SSD, and free space is automatically allocated to whichever volume needs it. The downside is that the output of "df" can be confusing at first if you're not used to it! (Maybe this feature is common on all OS's/filesystems now days, but I certainly could have used it back in my Linux-admin days. It was quite a revelation when I discovered it!)

macintosh-hd 3y ago
How does that work with Time Machine? I once considered doing that, but I was worried that Time Machine would gobble the entire drive.
- Reason077 3y ago
  Good question. I've only had it set up for a few months and so far Time Machine is only using 660 GB of my 2 TB SSD, backing up my MacBook's 512GB internal drive. So Time Machine is pretty space-efficient, but it will keep growing over time until it fills the entire backup drive since there is no limit on how old the backups it keeps can be[1]. I guess when it starts filling up I will just manually delete some old backups to free up space if I need it. Apparently, another alternative is to limit the size (set quota) of Time Machine's backup volume in Disk Utility. [1] Personally I wish this could be configured. I don't really care much about keeping old files, I just want to make sure I have a recent backup just in case my MacBook gets lost or stolen or it's SSD fails...
  - macintosh-hd 3y ago
    The way I set mine up is the Time Machine section of the drive has a quota capped at 1.5x the size of my internal drive, unfortunately you can’t edit quotas without formatting the drive. (Is there any functional difference between a quota and a partition then…? Weird…)
    - Reason077 3y ago
      Yeah, that's annoying that you can't edit quotas. But they are functionally different to a partition because the quota just limits the maximum size of the volume. If it's not filled to its quota, any unused space is still available for other volumes to use.

macintosh-hd 3y ago

How does that work with Time Machine? I once considered doing that, but I was worried that Time Machine would gobble the entire drive.

Reason077 3y ago
Good question. I've only had it set up for a few months and so far Time Machine is only using 660 GB of my 2 TB SSD, backing up my MacBook's 512GB internal drive. So Time Machine is pretty space-efficient, but it will keep growing over time until it fills the entire backup drive since there is no limit on how old the backups it keeps can be[1]. I guess when it starts filling up I will just manually delete some old backups to free up space if I need it. Apparently, another alternative is to limit the size (set quota) of Time Machine's backup volume in Disk Utility. [1] Personally I wish this could be configured. I don't really care much about keeping old files, I just want to make sure I have a recent backup just in case my MacBook gets lost or stolen or it's SSD fails...
- macintosh-hd 3y ago
  The way I set mine up is the Time Machine section of the drive has a quota capped at 1.5x the size of my internal drive, unfortunately you can’t edit quotas without formatting the drive. (Is there any functional difference between a quota and a partition then…? Weird…)
  - Reason077 3y ago
    Yeah, that's annoying that you can't edit quotas. But they are functionally different to a partition because the quota just limits the maximum size of the volume. If it's not filled to its quota, any unused space is still available for other volumes to use.