Arq is great, but my quibble with it is that, like all third-party backup solutions, it relies on scanning the file system. Any such program, Arq included, will take a very long time to run on a hard drive where absolutely nothing has changed.
What Time Machine does is use macOS's local database of pending changes, FSEvents. On the next backup cycle, it knows what's changed and doesn't need to scan unless the FSEvents database is missing or corrupt.
I'm looking forward to a time when Time Machine can take advantage of file system snapshotting, which apparently was a design goal for APFS. Snapshotting is used for Apple's Software Restore function now, but the Time Machine parts weren't ready for Catalina [1].
Arq is great, but my quibble with it is that, like all third-party backup solutions, it relies on scanning the file system. Any such program, Arq included, will take a very long time to run on a hard drive where absolutely nothing has changed.
What Time Machine does is use macOS's local database of pending changes, FSEvents. On the next backup cycle, it knows what's changed and doesn't need to scan unless the FSEvents database is missing or corrupt.
I'm looking forward to a time when Time Machine can take advantage of file system snapshotting, which apparently was a design goal for APFS. Snapshotting is used for Apple's Software Restore function now, but the Time Machine parts weren't ready for Catalina [1].
[1] https://eclecticlight.co/2019/08/16/are-we-ready-for-time-ma...