Change in Time Machine file naming

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mudbucker Author

Level 1

19 points

Change in Time Machine file naming

I just got an M1 MB Air yesterday, migrated from my old MB and did the initial backup to an external drive.

I was surprised to see the file naming has changed somewhat.

This shows backups from my previous MB and iMac to the same attached USB drive:

Here is the backup from the new MB to a different USB drive:

What I am concerned about is the ability to backup multiple machines to the same drive, as in the first screenshot. I don't see a top level Backups.backupdb folder as I've been seeing for many years.

Terminal shows this:

[Brian-M1-Air:/Volumes] brianrost% ls -l SanDisk\ 1TB-1/

total 8

drwxr-xr-x@ 5 root wheel 160 Dec 23 08:38 2022-12-23-091032.previous

-rw-r--r--@ 1 root wheel 583 Dec 23 09:10 backup_manifest.plist

I searched for info on this change and haven't turned up anything yet.

MacBook Air (M1, 2020), 8/8 cores, 16 GB/1TB

Mac OS 12.6.2 (21G320)

MacBook Air Apple Silicon

Posted on Dec 23, 2022 7:00 AM

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Answer 1

Top-ranking reply

PRP_53

Level 10

91,069 points

Dec 23, 2022 7:44 AM in response to mudbucker

If this were my setup, which it is not, I would Dedicate One Drive to the New Machine.

To put is plainly, having Several Machines backing up to One Drive can be done.

There is an inherent risk doing this.

All Eggs in One Basket ( metaphor) and the drive fails, which they do, scrambled Eggs

The Naming of Folders in TM Backup has changed especially since the Required APFS Drive format for TM Backup Drives.

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Answer 2

John Galt

Level 10

145,940 points

Dec 23, 2022 12:51 PM in response to mudbucker

I don't see a top level Backups.backupdb folder as I've been seeing for many years.

You will only see that folder on directly connected drives that have not yet been converted to use APFS. Non-Apple NAS devices can't use APFS.

Can you point me to any documentation that explains this?

Back up your Mac with Time Machine - Apple Support

"If the storage device contains Time Machine backups from another Mac, you might be asked to claim the existing backups so that they become part of the backups for this Mac. Or you can choose to start a new backup instead."

Time Machine is very conservative in that "start a new backup" will respect existing backups from another Mac, and will not delete them. It won't convert those volumes to APFS either, because it has no way to determine if that other Mac can recognize it.

You can back up multiple Macs to one TM drive if that is your preference, but the best practice is to use individual backup drives dedicated to each Mac (and ideally, more than just one backup drive for each Mac).

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Answer 3

mudbucker Author

Level 1

19 points

Dec 23, 2022 12:14 PM in response to mudbucker

I finally found some articles online describing how with APFS disks Time Machine automatically creates a separate volume for each machine being backed up to that disk. I verified this was the case using Disk Utility and Terminal.

I was able to back up my new machine to both the local Backup 3TB disk (Mac OS Extended) I mentioned in my initial post and my NAS backups (SMB).

Thanks for the answer.

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Answer 4

mudbucker Author

Level 1

19 points

Dec 23, 2022 11:45 AM in response to PRP_53

Thanks for the answer. Can you point me to any documentation that explains this?

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Change in Time Machine file naming

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