Time Machine question

[machenryr]

I've been using TM for a couple of years. The first was on a 5,1 Mac Pro. Then on a new 7,1 Mac Pro. The TM saved my butt on the 5,1 as there were problems right before I upgraded, though I still have that Mac and TM drive. I have the current TM backing up a 4 TB internal SSD to a 14 TB drive. I think it started backing up other disks as well. The last two weeks the target 14 TB drive says it's full. ???. I must be thinking backwards because when I go to options a click to exclude these disks from backup, the size required gets LARGER, not smaller. I'm confused as to how 14 TB can be filled backing up a 4 TB drive. Last week it said it needed an additional 2.5TB. Now it says it needs an additonal 6.25 TBs. Seriously confused.

I should just erase the disk and start over, but the pack rat I am I worry that I might need something down the line like I did last year from my 5,1 MP.

What am I missing?

 

[Brian33]

I'm confused as to how 14 TB can be filled backing up a 4 TB drive.

Time machine is designed to keep:
- hourly backups for the past 24 hours
- daily backups for the past month
- weekly backups for all previous months
The oldest backups are deleted when your disk becomes full.

(Taken from the TM preferences in Mojave.)

Your disk is full of older backups that contain files that have changed or been deleted from your source disks. Don't worry about it -- TM will just delete enough old ones to make room for the current backup.

I must be thinking backwards because when I go to options a click to exclude these disks from backup, the size required gets LARGER, not smaller.

This I have no explanation for -- when a disk is excluded, the backup size should definitely get smaller!

You can use Finder to check what drives have been backed up for any particular backup: double-click the drive, then "Backups.backupdb" , then your machine name, then either "Latest" or one of the date/time-stamped folders. You'll see a folder for each volume (drive) included in that backup. (Don't delete/move files within the backup using Finder, though.)

 

[Yebubbleman]

I've been using TM for a couple of years. The first was on a 5,1 Mac Pro. Then on a new 7,1 Mac Pro. The TM saved my butt on the 5,1 as there were problems right before I upgraded, though I still have that Mac and TM drive. I have the current TM backing up a 4 TB internal SSD to a 14 TB drive. I think it started backing up other disks as well. The last two weeks the target 14 TB drive says it's full. ???. I must be thinking backwards because when I go to options a click to exclude these disks from backup, the size required gets LARGER, not smaller. I'm confused as to how 14 TB can be filled backing up a 4 TB drive. Last week it said it needed an additional 2.5TB. Now it says it needs an additonal 6.25 TBs. Seriously confused.

I should just erase the disk and start over, but the pack rat I am I worry that I might need something down the line like I did last year from my 5,1 MP.

What am I missing?

Are your individual files large? Time Machine does one complete back-up of everything that it's going to back-up and then all subsequent back-ups are only changed files. That could be why your back-up drive is nearly full. I'm not sure as to what caused your back-up disk to grow LARGER after removing things to back-up. If you're fairly confident that you won't need to undelete anything, you may want to reformat your Time Machine drive and have it do the initial back-up from scratch. I do this from time to time when I notice the drive acting screwy. Though, admittedly, most of my data is in Dropbox these days (and my music library is on multiple computers with a single USB flash drive being what copies things between them), so I'm not really using Time Machine all that much these days. (Though I do help and assist many a user that still does use Time Machine.)