How to see what Time Machine is backing up every hour?

[djc6]

Time Machine is backing up 2-3GB of data every hour, all day long even when I don't use my computer for days. How do I figure out whats its backing up?

I came across BackupLoupe but I've looking if there is a free way to solve this mystery first. I don't mind Terminal, just not sure what tool I would use.

 

[Rastafabi]

It is no longer maintained and might not work with the modern APFS TimeMachine layout, but you could try TimeTracker.

 

[bogdanw]

"TimeMachineStatus is a little menu bar application for macOS which aims to show more useful information than the system default."
https://github.com/lukepistrol/TimeMachineStatus

 

[Mike Boreham]

https://www.soma-zone.com/BackupLoupe/

 

[gilby101]

Time Machine is backing up 2-3GB of data every hour

Doesn't surprise me. The every hour backup sizes are not the most important size (as they get thinned after 24 hours to one a day). What is more critical is the files unique to each backup of the daily and weekly backups.

I came across BackupLoupe but I've looking if there is a free way to solve this mystery first.

You don't need to pay for ? days. There isn't anything else, AFAIK.

BackupLoupe probably over estimates sizes because (I think) it does not take account of APFS clones and compression. But it does work well for identifying everything that is being backed up and finding what is large and could be excluded. I have used it for many years.

 

[djc6]

I've not been able to prove this since I didn't want to pay for BackupLoupe, but I think the issue my Windows 10 VM. I recently started playing with Windows 10 inside a VM in VMware Fusion and usually just leave the VM running. It seems to cause a lot of churn since the VM I'm assuming is changing often from log messages, etc.. little changes.

 

[gilby101]

but I think the issue my Windows 10 VM.

As you have discovered, Virtual Machines should always be excluded from TM. Take other steps to provide whatever level of backup you need. This could be:
1) Manual copy when it is not running, keeping only a few (or maybe just 1) copy.
2) Automatic copy using Carbon Copy Cloner only retaining a few versions.
3) Backup using a backup product inside the VM;
4) Backup using virtual machine snapshots. Fusion VM snapshots can be automated with Vimalin https://www.vimalin.com/