Due to a problem, I want to copy the contents of an external disk with a corruption in one partition.  The corrupted partition is HFS+ and the other is APFS. The APFS partition is a Time Machine backup, and thus many operations on it are disabled by SIP or ACLs or xattr.

Most of the files on the problem partition are still accessible.

What is the best way to partition a new drive into two APFS volumes of approximately the same size and usage (one for Time Machine and one for interactive archiving)?


1 Answer 1


From the Disk Utility Guide:

Apple File System (APFS) allocates disk space on demand. When a single APFS container (partition) has multiple volumes, the container’s free space is shared and can be allocated to any of the individual volumes as needed. Each volume uses only part of the overall container, so the available space is the total size of the container, minus the size of all volumes in the container.


if you want to manually manage APFS volume allocation, click Size Options, enter values in the fields, then click OK

  • Reserve Size: The optional reserve size ensures that the amount of storage remains available for this volume.
  • Quota Size: The optional quota size limits how much storage the volume can allocate.

This configuration works perfectly well when one volume of the container is reserved for Time Machine and the other(s) are used for other storage.

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