Time Machine minimum space needed

[Macbertha]

Want to partition a 4TB external hard drive to backup my iMac (1TB) with Time Machine and to store music audio and video files. Have seen recommendations to allot 2 to 3 times the size of the machine that is to be backed up to provide space to handle the multiple daily backups created by Time Machine.

My purpose in using Time Machine is to provide a basic backup of what is on my iMac today. I am not interested in what my iMac "looked like" three months ago.

With the desire for just one or two, at most, backups, what is the minimum space I should partition to handle a 1TB iMac using Monterey OS?

Thanks very much for your recommendations.

 

[Weaselboy]

Most people recommend you need a TM volume that is around 2X the amount of data you plan on having on the Mac.

The Mac drive size does not really matter. If you have a 1TB Mac with only 200GB of data on it for example, a 400GB TM volume would give you plenty of room for some versioning storage.

 

[MarkC426]

My purpose in using Time Machine is to provide a basic backup of what is on my iMac today. I am not interested in what my iMac "looked like" three months ago.

That being said, an incremental backup can be invaluable.
For example, you could work on a 'file' all day re-save it, then realise the next day it was the wrong file.
With TM, you can go back to 5 hours ago (or whenever) and get your original back.

Also having your music/video on the same drive will not be backed up.
Even if you copy it to the TM partition, if the drive fails, it all fails.

 

[Macbertha]

Most people recommend you need a TM volume that is around 2X the amount of data you plan on having on the Mac.

The Mac drive size does not really matter. If you have a 1TB Mac with only 200GB of data on it for example, a 400GB TM volume would give you plenty of room for some versioning storage.

Thanks for this information.

 

[Macbertha]

That being said, an incremental backup can be invaluable.
For example, you could work on a 'file' all day re-save it, then realise the next day it was the wrong file.
With TM, you can go back to 5 hours ago (or whenever) and get your original back.

Also having your music/video on the same drive will not be backed up.
Even if you copy it to the TM partition, if the drive fails, it all fails.

Interesting point about working on the wrong file. As for music/video files, those are backed up elsewhere. Thanks for the info.

 

[MajorFubar]

TM makes incremental backups, and from what I understand, the incremental backups only back up whatever has changed since the last backup. Consequently its backups aren't each the same size as the all the data on your drive. I back up an iMac's 1TB drive, which is three quarters full, to a 2TB drive, and have never encountered running out of space, because I don't routinely change gigabytes of data on it every day.

 

[Fishrrman]

OP wrote:
"My purpose in using Time Machine is to provide a basic backup of what is on my iMac today. I am not interested in what my iMac "looked like" three months ago. "

Well, in that case you SHOULD NOT BE USING time machine.
Rather, you should use either CarbonCopyCloner or SuperDuper.

CCC and SD are "cloning" utilities.
They produce an EXACT COPY of your drive "as it looks like" at the time you create the clone.

If you do it right, the clones are even bootable -- they will boot and run your Mac just like the internal drive. VERY handy to have in emergencies and you CANNOT DO THIS with time machine backups.

Granted, CCC and SD aren't free like tm. But either will serve you well, far better than tm.

You can download both for free and use them for 30 days.
If you're not happy, just delete the cloned backup and go back to tm.

A WORD ABOUT SPACE:
If you use either CCC or SD, your backup drive doesn't need to be any larger than your source drive, again, because the backup is an exact copy of the source.

 

[Macbertha]

OP wrote:
"My purpose in using Time Machine is to provide a basic backup of what is on my iMac today. I am not interested in what my iMac "looked like" three months ago. "

Well, in that case you SHOULD NOT BE USING time machine.
Rather, you should use either CarbonCopyCloner or SuperDuper.

CCC and SD are "cloning" utilities.
They produce an EXACT COPY of your drive "as it looks like" at the time you create the clone.

If you do it right, the clones are even bootable -- they will boot and run your Mac just like the internal drive. VERY handy to have in emergencies and you CANNOT DO THIS with time machine backups.

Granted, CCC and SD aren't free like tm. But either will serve you well, far better than tm.

You can download both for free and use them for 30 days.
If you're not happy, just delete the cloned backup and go back to tm.

A WORD ABOUT SPACE:
If you use either CCC or SD, your backup drive doesn't need to be any larger than your source drive, again, because the backup is an exact copy of the source.

Valuable information. Think I'll give one of these a try. Thanks.

After another cup of coffee, couldn't I just drag and copy my HD to the external HD at the close of business each day?

 

[MarkC426]

This wouldn't copy all the necessary files to create a bootable clone.

For reference, Superduper is free forever.
With the free version you have to do a full backup every time.
For the small fee of £25 you can do incremental backups (it just updates what has changed on the copy).

https://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html

 

[Macbertha]

This wouldn't copy all the necessary files to create a bootable clone.

For reference, Superduper is free forever.
With the free version you have to do a full backup every time.
For the small fee of £25 you can do incremental backups (it just updates what has changed on the copy).

https://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html

Just an amateur here, so unaware of the technical workings. Will explore some of the suggested utilities. Thanks.

 

[MarkC426]

There is no 'technical' hoohar with either SuperDuper or Carbon Copy.....
Both have a very user friendly interface with a source and destination disks selection.

 

[Macbertha]

There is no 'technical' hoohar with either SuperDuper or Carbon Copy.....
Both have a very user friendly interface with a source and destination disks selection.

Noted. Thanks again.

 

[MarkC426]

FWIW I have TM backing up all my internal drives and also have external clones of each drive.

 

[Fishrrman]

"couldn't I just drag and copy my HD to the external HD at the close of business each day?"

NO.
This doesn't work with the Mac OS.

 

[Macbertha]

"couldn't I just drag and copy my HD to the external HD at the close of business each day?"

NO.
This doesn't work with the Mac OS.

Valuable information. Thank you.