How much storage does time machine really need?

Question

lulambert Author

Level 1

4 points

How much storage does time machine really need?

Dear Apple Community.

My iMac has 2 TB in internal storage.

I am currently using a 4 TB Seagate external hard drive for FCPX and other files back up.

I am also using a 12 TB WD easy store drive as time machine.

I am wondering if I am wasting TB with time machine, since my internal storage is 2TB.

Time machine will never need to back up more that 2TB, am I right?

Should I have set up my 12 TB hard drive as external storage for my future FCPX libraries and re-format the 4TB Seagate as time machine?

iMac 27″ 5K, macOS 10.15

Posted on Jul 7, 2020 1:30 PM

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Answer 1

Tesserax

Level 10

159,812 points

Jul 8, 2020 8:50 AM in response to lulambert

lulambert wrote:

...follow up question to what you say is, would 12TB (which I am using now) be too much time machine for a 2TB iMac considering that it is actually 6 times the space, not just 2 or 3 times?

Yes. 12 TB would be "too much" space to hold TM backups of a 2 TB notebook. I would suggest that you dedicate at least 4 TB on this drive for TM and use the rest for your storage goals.

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Answer 2

Jul 7, 2020 8:00 PM in response to lulambert

Time machine will use up whatever space you give it. It will also save old backups as long as there is space. That is why you want 2 to 3 times the space. If you don't care about old files, you can use a smaller space.

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Answer 3

lulambert Author

Level 1

4 points

Jul 8, 2020 8:06 AM in response to Keith Barkley

"Time machine will use up whatever space you give it. It will also save old backups as long as there is space. That is why you want 2 to 3 times the space. If you don't care about old files, you can use a smaller space."

Thank you, Keith. Now, maybe a follow up question to what you say is, would 12TB (which I am using now) be too much time machine for a 2TB iMac considering that it is actually 6 times the space, not just 2 or 3 times? I am just wondering if 12TB is a waste of space that I could re-format into a simple storage hard drive and get less memory for Time Machine with a new device of say, 6TB. I mean, my "old files" are 3 years old and I normally back them up in external hard drives anyway.

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Answer 4

lulambert Author

Level 1

4 points

Jul 7, 2020 2:00 PM in response to lulambert

"The historical rule is a Time Machine drive that is 2.5 to 3x the capacity of the internal drive that is to be backed up."

Does that mean 4TB is too small for time machine? Conversely, isn't 12TB way too much for time machine?

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Answer 5

dialabrain

Level 10

137,567 points

Jul 7, 2020 1:33 PM in response to lulambert

The normal recommendation for Time Mchine is 2 to 3 times the size of your internal.

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Answer 6

VikingOSX

Level 10

126,588 points

Jul 7, 2020 1:34 PM in response to lulambert

The historical rule is a Time Machine drive that is 2.5 to 3x the capacity of the internal drive that is to be backed up.

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Answer 7

KiltedTim

Level 10

232,178 points

Jul 8, 2020 8:54 AM in response to lulambert

Keep in mind that if you do not explicitly exclude the 4 TB external drive you have connected, Time Machine will also back that up.

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Answer 8

Jul 8, 2020 8:32 AM in response to lulambert

If you already have a 12 TB, it can't hurt, but I would not purchase one for TIme machine. If not being able to go back to old revisions you have deleted can cost you money, you might want 12TB. Personally, I think it is overkill.

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Answer 9

lulambert Author

Level 1

4 points

Jul 7, 2020 6:43 PM in response to BDAqua

"Are you saving files as backups as well as using the same drive for Time Machine?

If so very bad strategy. :)"

Nope. That is NOT what I am doing. I was clear: 4TB is an external drive for back up files. 12TB is the time machine. Please read the original question before answering.

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