Time machine not backing up

[streetsandtheatres]

I have a 12TB external drive for my time machine backup. It's been fine since September 2020. But now it's saying that backups fail because of a lack of space. Currently 600GB is available, and the calculated size of the full backup is 6.54TB.

When I open the drive and look in the backups folder it shows a long list of backups - some 3000 folders (all of which seems to have folders/files inside). But in the preferences it says 'Oldest backup 12 April 2021' and 'Latest backup 12 April 2021.'

I'm wondering how to fix this?

Thanks.

 

[gilby101]

macOS version? And, if BS, is the TM drive APFS or HFS+? Are the 3000 folders the dated ones that TM makes?

 

[streetsandtheatres]

Catalina (10.15.7). Now that you ask my computer may have installed a minor update at around the time this problem arose (but maybe not).
Mac OS Extended (Journaled).
Yes, the 3000 folders are the ones that TM makes: titles are dates and times.

 

[gilby101]

Thanks for clearing up versions - Big Sur changes everything!

TM makes a backup every hour, but should thin past backups to one backup for every hour in the past 24 hours, and one per day for the last month, and before that one per week. So 3000 folders when thinning properly indicates 50 years of backups - seems unlikely.

My guess is that TM is not correctly thinning and that you have one backup for every hour since you started using that TM disk. Is that right?

Question: Have you done anything to control the timing of TM backups? Or is it just the default timing (once per hour without you attempting to force it)? There are some apps around which take control of TM's timing and, if you have installed one, could be the cause of your problem.

But in the preferences it says 'Oldest backup 12 April 2021' and 'Latest backup 12 April 2021.'

Never heard of that before. There may be a serious problem - e.g. old backups not accessible. Just confirm that you can get to the old backups in Finder and copy a few documents back to your source disks.

I suspect your solution will be to start again with Time Machine, but don't rush into that until you are sure there is no other way and that there is some confidence that thinning will work properly.

Whilst it would take a long time to scan the disk, BackupLoupe would show you which are the large backups.

 

[streetsandtheatres]

Thanks for clearing up versions - Big Sur changes everything!

OK

TM makes a backup every hour, but should thin past backups to one backup for every hour in the past 24 hours, and one per day for the last month, and before that one per week. So 3000 folders when thinning properly indicates 50 years of backups - seems unlikely.

My guess is that TM is not correctly thinning and that you have one backup for every hour since you started using that TM disk. Is that right?

Yes, that's right.

Question: Have you done anything to control the timing of TM backups? Or is it just the default timing (once per hour without you attempting to force it)? There are some apps around which take control of TM's timing and, if you have installed one, could be the cause of your problem.

I haven't changed anything. I have been using Backblaze for the since about February.

Never heard of that before. There may be a serious problem - e.g. old backups not accessible. Just confirm that you can get to the old backups in Finder and copy a few documents back to your source disks.

Yes, I seem to be able to do that. I tried a few files from well before the 12 April.
Looking again in the preferences, and clicking the red ! it says:

'The backup disk needs 1.10 TB for the backup but only 604.79 GB are available. Select a larger backup disk or make the backup smaller by excluding files.'

I suspect your solution will be to start again with Time Machine, but don't rush into that until you are sure there is no other way and that there is some confidence that thinning will work properly.

Whilst it would take a long time to scan the disk, BackupLoupe would show you which are the large backups.

OK thanks.

 

[streetsandtheatres]

Thanks for clearing up versions - Big Sur changes everything!

TM makes a backup every hour, but should thin past backups to one backup for every hour in the past 24 hours, and one per day for the last month, and before that one per week. So 3000 folders when thinning properly indicates 50 years of backups - seems unlikely.

My guess is that TM is not correctly thinning and that you have one backup for every hour since you started using that TM disk. Is that right?

Question: Have you done anything to control the timing of TM backups? Or is it just the default timing (once per hour without you attempting to force it)? There are some apps around which take control of TM's timing and, if you have installed one, could be the cause of your problem.



Never heard of that before. There may be a serious problem - e.g. old backups not accessible. Just confirm that you can get to the old backups in Finder and copy a few documents back to your source disks.

I suspect your solution will be to start again with Time Machine, but don't rush into that until you are sure there is no other way and that there is some confidence that thinning will work properly.

Whilst it would take a long time to scan the disk, BackupLoupe would show you which are the large backups.

Could I manually delete some of the old backups? EDIT: Actually I don't think I want to do that. Seems like trouble.

 

[gilby101]

Could I manually delete some of the old backups? EDIT: Actually I don't think I want to do that. Seems like trouble.

Yes, you can. But as you say it might be asking for trouble.

sudo tmutil delete <path with backup date/time folder>

The clean thing is to get a new backup disk and start again with that (keeping your old one on one side - just in case).

But it would be good to understand why thinning has failed. We need someone else to chime in on that.

I have been using Backblaze for the since about February.

That wouldn't touch Time Machine. Revieved that you do have another backup in case your TM backup becomes corrupted - but it doesn't seem corrupted, just not thinned.

'The backup disk needs 1.10 TB for the backup but only 604.79 GB are available. Select a larger backup disk or make the backup smaller by excluding files.'

TM does overestimate the space it requires. Nevertheless that is a big jump for an incremental backup. Have you been moving your data around on the source disks? That could explain the large jump.

I may well be getting too far ahead, but in the long run I think you need to keep more of an eye on your TM backups - it is not really set and forget for large backups of multiple disks - particularly if data is moved between disks (or even folders).

 

[streetsandtheatres]

TM does overestimate the space it requires. Nevertheless that is a big jump for an incremental backup. Have you been moving your data around on the source disks? That could explain the large jump.

I may well be getting too far ahead, but in the long run I think you need to keep more of an eye on your TM backups - it is not really set and forget for large backups of multiple disks - particularly if data is moved between disks (or even folders).

I have been adding ca.100GB/week over the past couple of months. Video files for editing...

 

[mr.datsun]

I have this problem. I can wind back a few weeks/months. The file is there but it has today's date. If I restore and keep the old file both files are the same.