Time Machine weirdness

[Cave Man]

I bought an M1 Mac mini a few months ago but did not set up a Time Machine hard drive until a few days ago. The Mini has a 2 TB SSD, and two external drives (2 TB Thunderbolt m2 PCIe and 4 TB USB3 hard drive). Total disk space used is about 5.3 TB:

0.9TB internal
3.7TB HD
0.7TB Thunderbolt

The external USB3 Time Machine hard drive is 8 TB initialized as APFS. However, after Time Machine "completed" its initial backup, there are still 7.1 TB available on the Time Machine volume, so clearly something is not right. When I enter Time Machine, all three disks show up, so it's not because I have inadvertently excluded drives.

I have never had this problem prior to Monterey or having this new M1 Mac mini, so I'm struggling to understand what the problem might be. Any ideas? TIA.

 

[Cave Man]

Just bumping this in case anyone has an idea what's going on. I reinitialized the 8 TB Time Machine drive (APSF) and after backing up there is still 7.11 TB available on the drive. This can't be correct.

 

[chscag]

Here's a thread from another Mac Forum that may help with your Time Machine problem. The thread is quite long but post #227 is what you need to look at:

https://www.mac-forums.com/threads/imac-m1-monterey-running-slowly.369037/page-12#post-1901976

 

[BigBlur]

Time Machine excludes external drives by default. Have you gone into Time Machine Preferences and removed them from being excluded? (System Preferences -> Time Machine -> Options...)

Also, it's generally recommended that a Time Machine drive is around 2-4 times the size of the data you're backing up. You may be okay-ish now (5.3 TB of data, and a 8 TB Time Machine drive). However, as your drives fill up and more files are changed, there will be less version history on the Time Machine drive to restore from. Just as an example, even if you only backed up your 2 TB internal drive, the backup will grow over time as it keeps track of all the file changes until it fills the 8 TB Time Machine drive. When the Time Machine drive gets full, it starts deleting the oldest versions your data to make room for new backups. You may want to consider if you really need to back up everything on your external drives with Time Machine...or even at all. Another backup method might be more suitable for the external drives, or have a bigger Time Machine drive.

 

[gilby101]

When I enter Time Machine, all three disks show up, so it's not because I have inadvertently excluded drives.

Use Finder to inspect the TM disk. Do you see files for all three disks? If not, see @BigBlur's post.

 

[Cave Man]

Here's a thread from another Mac Forum that may help with your Time Machine problem. The thread is quite long but post #227 is what you need to look at:

https://www.mac-forums.com/threads/imac-m1-monterey-running-slowly.369037/page-12#post-1901976

Hmm, that's going to take some time, but I don't have any other users on my Mac mini so I'm not sure that applies to my situation.

 

[Cave Man]

Time Machine excludes external drives by default. Have you gone into Time Machine Preferences and removed them from being excluded? (System Preferences -> Time Machine -> Options...)

Also, it's generally recommended that a Time Machine drive is around 2-4 times the size of the data you're backing up. You may be okay-ish now (5.3 TB of data, and a 8 TB Time Machine drive). However, as your drives fill up and more files are changed, there will be less version history on the Time Machine drive to restore from. Just as an example, even if you only backed up your 2 TB internal drive, the backup will grow over time as it keeps track of all the file changes until it fills the 8 TB Time Machine drive. When the Time Machine drive gets full, it starts deleting the oldest versions your data to make room for new backups. You may want to consider if you really need to back up everything on your external drives with Time Machine...or even at all. Another backup method might be more suitable for the external drives, or have a bigger Time Machine drive.

I don't see a way to include external drives, only to exclude them (attached screen shot). The drives that are not getting backed up are "Data" and "Photos". Am I missing something?

 

[BigBlur]

I don't see a way to include external drives, only to exclude them (attached screen shot). The drives that are not getting backed up are "Data" and "Photos". Am I missing something? View attachment 1948012

Select those two drives, and then click the - button at the bottom of the screen. That should remove them from the list.

 

[Cave Man]

Use Finder to inspect the TM disk. Do you see files for all three disks? If not, see @BigBlur's post.

Right, the only thing that is getting backed up by TM is the internal SSD. In the attached, "Data" is the internal SSD APFS volume, not the external hard disk named "Data". So, trying to figure out how to add the two external drives.

 

[Cave Man]

Select the drive, and then click the - button at the bottom of the screen. That should remove them from the list.

OMG! How dumb of me. To my brain, that isn't intuitive. I hope it's working now. Sheesh.

Thanks much.

 

[Cave Man]

Now I have this error message upon trying to backup. I only have one disk named "Macintosh HD" so not sure how to proceed.

 

[BigBlur]

Now I have this error message upon trying to backup. I only have one disk named "Macintosh HD" so not sure how to proceed.
View attachment 1948019

My guess is that it's not liking the external drive named 'Data' since the internal one you're backing up is also called 'Data'. That doesn't really jive with the error saying rename one of the disks named "Macintosh HD" though. You could try renaming the external Data drive to see if that works. (Or exclude it again to see if the error goes away and starts backing up the Photos drive.)

 

[Cave Man]

OK, I've reinitialized the Time Machine volume and have renamed the hard drive "Data" to "Files". Fingers crossed that this solves it. Thanks for your help.