Can you Partition a Time Machine External HD to share with another Area

[Microman]

Have this 5 TB external Drive, that we are going to use for Time Machine. Is it possible to partition part of it to hold a CCC or Super Duper backup image as well?

Thanks.

Or maybe just an area to store personal files, that would be easier to get to, but are backed up.

[mikebw]

You don't even have to partition it. TM will create a backups folder and you can use the rest of the drive for whatever you want.

[jdc]

mikebw wrote:
You don't even have to partition it. TM will create a backups folder and you can use the rest of the drive for whatever you want.

This. TM doesn't care what else might be on a drive.

Is the SD going to be a "bootable" backup?

[Sarcany]

jdc wrote:
[quote=mikebw]
You don't even have to partition it. TM will create a backups folder and you can use the rest of the drive for whatever you want.

This. TM doesn't care what else might be on a drive.
Yes, it does. It works under the assumption that it has an entire volume to itself. It will fill the drive and throw errors if you put anything else on the same volume with the TM backups.

So, yes. Use the Disk Utility to partition the drive for your CCC backup.

[jdc]

Never seen it. At least a dozen clients with TM and CCC backips on the same drive.

Have to remind them often its not a "double" backup since its the same drive, but seems fine.

True that TM just keeps eating the drive.

[Microman]

So a Big Sur computer, that has an external drive formatted as Extended, gets converted by Big Sur to APFS, and putting an important file or folder on the Time Machine drive might get eaten or written over by Time Machine?

[Sarcany]

Microman wrote:
So a Big Sur computer, that has an external drive formatted as Extended, gets converted by Big Sur to APFS, and putting an important file or folder on the Time Machine drive might get eaten or written over by Time Machine?

The file won't get over-written.

But the backup daemon will not factor in that used-capacity from your other files when calculating the space available for a backup.

Eventually, this will cause it to throw a "disk full" error and stop backing up.

So, you prep the disk by erasing and partitioning it with two volumes. One for your Time Machine backup and one for your CCC clone. Don't use APFS "containers" if you see a message about that when you opt to partition in the Disk Utility in Big Sur. You want real "partitions" for this purpose.

And the partitions do not have to be of equal capacity. If your boot drive is 1TB, there's no particular reason why you need to allocate more than a TB to your clone. Meanwhile, Time Machine loves to gobble disk space, so it's a good idea to allocate more than the capacity of your boot drive to your Time Machine backup.

[Microman]

OK, I am thinking of calling my daughter and walking her thru Reformating the external 5 TB Time Machine Drive. She is running Big Sur, I understand that even though I formatted HFS? that time machine on Big Sur now converted it to APFS.

So I would have her reformat the drive, and then partition it with two Partitions. One 3 TB for Time Machine and one 2 TB to match a 2 TB drive she has to copy important files off of the MacBook Pro Desktop. Thus giving 2 2 TB locations to keep identical set of IMPORTANT files.

Anything I missed. Formatting, etc... and options to choose? Since she has only done one TM backup, it won't be a big loss, and since all is working well with her new 1 TB M.2 with Adapter... this should be good for her.

OH and the 2 TB does hold a CCC backup of her HD, so maybe store an image backup on both 2 TB areas. I was a little confused with CCC when we made an image backup. I forget the term it used, image with par... something

My Catalina says this, but I suppose Big Sur would be different. Probably reformat her computer with 2 APFS partition 3,2 size, and then allocate 3 as the TM backup?

Thanks..