How to use one external drive to back up 2-3 computers

We are thinking or purchasing either a 2 TB Seagate Backup Plus Slim or a Western Digital’s 4 TB My Book suggested to us by someone who trusts NYT’s Wirecutter.

Thing is between the two of us we have less that 2TB to back-up and little disposable income. Is there a way to use a single external hard drive to back up both computers at different times of course? If so, what do we need to tell the external hard drive to not be erased the other computer’s data? What is this type of set up called?

Also…would you second the above products? If there are other simple solutions, we are pen to those too. We are also favoring using SuperDuper instead of Time Machine.

I back up a couple of computers to one drive like that, using SuperDuper. I believe I created partitions for each backup, but I’m sure the SuperDuper instructions would have guidance on that.

Although I’ve done the same thing (using partitions), it’s not really a great idea because if the drive goes bad you lose backups for both machines. Since the price of drives has fallen, I abandoned this approach and I use two sets of drives, one set per machine.

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Thanks @jec0047. True that and I was just reading about the possibility of failure. What external hard drives are you using?

Agreed @tonycraine. One Drive - you mean the Microsoft service? I will email Dave and ask him for guidance. Good idea!

Sorry, I meant one disk. But, to @jec0047’s point, I also back up both of those computers to Time Machine as well.

I have 4 Seagate 2T drives. Last time I bought them they were 79 USD on Amazon.

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I use Time Machine as well.

I have a pair of 4Tb portable drives that I use for backups. One lives at my wife’s parents just in case, and the other lives at our home.

Each portable drive has three partitions. 500Gb for my MacBook Pro, 500Gb for my wife’s MacBook Pro and the rest is used by Time Machine from both of our computers.

Every Sunday I backup to the portable drive we have at home using SuperDuper! as well as Time Machine from both our laptops. My wife goes for dinner on Sunday nights and takes that fresh backup drive with her to exchange it for the other portable.

I also have a 12Tb Synology NAS that we use for hourly Time Machine backups along with running a Plex server for our media collection. Along with that I have a couple of old Mac Minis with attached 2Tb drives that are also used by Time Machine on both of our laptops.

SuperDuper! Is more that awesome and has saved our bacon on numerous occasions.

I’m anxiously waiting for the next update to SuperDuper! So I can switch over to Big Sur.


@Larry_Wilson, what model is your Synology?

I have this seagate 2TB External HDD It’s been ok for me. The end that connects to the hard drive seems loose and can be accidentally disconnected. I don’t know if that’s a function of the cable or the port.

If I were you, I’d go for the most space within your budget.

You could setup multiple partitions for each computer that you’re backing up for superDuper. I would also have a separate partition for Time Machine since it’s free and will save multiple versions for you. You can share that like a time machine server

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I’d suggeste getting at least 2 different drives, one for each computer. If one drive fails you will at least have the other backup ok.

I currently have 2 machines (iMac and Laptop) and have 7 backups. 3 separate hard drives for each machine that get used in rotation and both machines also backup up to our NAS server each night.

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it is the Synology DS1019+

It’s been rock solid since I set it up a year ago

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You can use the same HD for multiple computers. The suggestion of 2 HD’s for backup make more sense than “putting all your eggs in one basket” than a single source. HD prices are dropping because of the Holiday season. I would recommend buying two 4TB drives (same model) and keep on at home and the other in a different location. Desktop HD’s are normally less expensive than portable HD’s. SSD models will be the most expensive.

I would also suggest both SuperDuper and Time Machine as good options for your backups.