Time Machine Question

[CPmav]

I'm hoping to move some of my large video files off of my Mac SSD and onto an external SSD. My question is regarding the behavior of Time Machine. I keep my backups on a second SSD strictly for Time Machine, and I'm curious if my backed up files will remain on my Time Machine SSD after deleting the files on my Mac SSD. If they do stay on my Time Machine SSD, if I begin to run out of storage for future backups will macOS ask prior to deleting them?

I appreciate the help!!

 

[ovbacon]

Time machine captures and instance in time so the older TM backups will have files that you delete since that is the whole point of TM. You can also have TM make backups of external drives. My TM makes a backup of my internal SSD, an external SSD and an external HDD.

 

[hg.wells]

I would advise against this if these videos are important. It’s not a backup if the only copy of the file is on the Time Machine drive.

 

[gilby101]

if I begin to run out of storage for future backups will macOS ask prior to deleting them?

To the best of my knowledge: No! When the TM disk runs out of storage, TM will automatically delete the oldest backups (without telling you). And that is ALL of the oldest backup. If there are files unique to the oldest backup, they will be gone!

So don't delete files from your source disk(s) if you want TM to preserve them. TM is a disaster recovery backup, it is not an archive.

What you could do:
1) After you move your files to an external permanently connected disk, you can include that disk in your TM backup. Then the files will be safe. Might well cause a sudden jump is space used on the TM destination - so allow for that.
2) Backup your video files by some other method - e.g. copy to yet another disk or to a cloud provider.

 

[CPmav]

Thanks everyone, really appreciate the advice!! Backing up the external SSD is a great idea, can't believe I didn't think of that lol

 

[jaw04005]

Time Machine will warn you before it starts deleting old backups. Now that SD cards have gotten so much larger—I just start with a fresh card.

 

[ChrisA]

I'm hoping to move some of my large video files off of my Mac SSD and onto an external SSD. My question is regarding the behavior of Time Machine. I keep my backups on a second SSD strictly for Time Machine, and I'm curious if my backed up files will remain on my Time Machine SSD after deleting the files on my Mac SSD. If they do stay on my Time Machine SSD, if I begin to run out of storage for future backups will macOS ask prior to deleting them?

I appreciate the help!!

First off, you might want to use a larger hard drive for Time Machine (TM). Buy the largest one you can afford. Using SSD is faster but there is not reason to worry about speed. Even a "slow" hard drive is faster then you need.


TM will keep all versions of your old data. When you make a change or edit, the new version is saved but the old versions are not deleted. Well, until the disk gets full then the oldest data is deleted to make room for the new data. With a large enough TM disk you old video files will remain for a LONG time.

But after you move the video files TM will see them as "new data" and copy them to the TM disk.

How long the old versions of the files are kept and how many copies f those old files are kept, depends on the size of the TM disk. In general, you'd like the TM disk to be at least twice the size of the data on your computer counting all the internal and external drives. The TM drive should be much larger than the sum of all the data. This is why I said to use a hard drive, 8Gb or even 16GB hard drives are now affordable

Also if you are really concerned, you can connect two or more TM drives and macOS will rotate between them and keep any number of TM drives up to date. You can keep one or more of the TM drives in a fire safe and rotate then as you like and then your data will be save from lightning strikes on the power line, house fires, and such.

If the TM drive(s) are large enough deleted dat might be saved for years. But this is not dependable archive storage. because eventually, TM will start deleting the oldest data.

 

[gilby101]

Time Machine will warn you before it starts deleting old backups.

Are you sure about warning? My wife's 2012 Mac mini has a TM disk which is now 10 years old and the TM has been pruned of all backups older than 2017 without any warnings - about one a week.

 

[ChrisA]

Are you sure about warning? My wife's 2012 Mac mini has a TM disk which is now 10 years old and the TM has been pruned of all backups older than 2017 without any warnings - about one a week.

Yes, it seems to have changed. There used to be more options you could set.

 

[NoBoMac]

Are you sure about warning? My wife's 2012 Mac mini has a TM disk which is now 10 years old and the TM has been pruned of all backups older than 2017 without any warnings - about one a week.

I seem to recall you get A notification about this, the first time old backups need to be pruned. After that, just does it without any new alerts.

 

[gilby101]

I seem to recall you get A notification about this, the first time old backups need to be pruned. After that, just does it without any new alerts.

You are probably right about this. My memory of the first pruning is very hazy.