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Hi,
I currently boot my 2015 iMac with Big Sur from an external SSD. I plan to buy a supplementary 2016 - 15" MacBook Pro also running Big Sur to have in another office.
Cheers
Matty
You don’t actually have to partition the SSD to use it for TimeMachine with two different computers. TM will ‘know’ which computer it is connected to and keep totally separate backups. That’s both good news and bad - you’ll be duplicating files and apps with two backups and there’s no getting around that.
We generally recommend the TM drive be at least twice as large as the amount of space being backed up and I like to make that 3 times to allow for growth of the source files. So figure out how much space both drives are already using, do the math and if that is close to the capacity of the SSD consider getting a larger SSD.
All that said, I don’t consider a single TimeMachine backup a total strategy. What happens if a thief walks in, takes both Macs and the hard drives and printer? This past winter it happened to my neighbor. I recommend at least two backups with one of them being off-site. To accomplish this I have two backup drives. One stays at home all week and goes into work on Friday. The other is in my desk at work all week and comes home on Friday.
You don’t actually have to partition the SSD to use it for TimeMachine with two different computers. TM will ‘know’ which computer it is connected to and keep totally separate backups. That’s both good news and bad - you’ll be duplicating files and apps with two backups and there’s no getting around that.
We generally recommend the TM drive be at least twice as large as the amount of space being backed up and I like to make that 3 times to allow for growth of the source files. So figure out how much space both drives are already using, do the math and if that is close to the capacity of the SSD consider getting a larger SSD.
All that said, I don’t consider a single TimeMachine backup a total strategy. What happens if a thief walks in, takes both Macs and the hard drives and printer? This past winter it happened to my neighbor. I recommend at least two backups with one of them being off-site. To accomplish this I have two backup drives. One stays at home all week and goes into work on Friday. The other is in my desk at work all week and comes home on Friday.
Hi Globibahn,
That is a bad idea. The SSD is configured for the iMac. It should only be used with one Mac. Plus, the internal SSD on a 2016 MacBook Pro is faster than an external SSD.
You can, however, partition this external SSD into two boot volumes, and have two boot volumes for each Mac, if your heart is set on using this external SSD for the MacBook Pro: Partition a physical disk in Disk Utility on Mac - Apple Support or Add, delete, or erase APFS volumes in Disk Utility on Mac - Apple Support.
You can use the same SSD as a Time Machine drive for the two. Just partition it: Partition a physical disk in Disk Utility on Mac - Apple Support or Add, delete, or erase APFS volumes in Disk Utility on Mac - Apple Support. PLEASE make sure there is enough room on the SSD for the backups of both Macs!
But, a warning! If one of these SSDs go, there goes something for BOTH Macs. I wouldn't ever do this, but is it technically possible.
Cheers,
Jack
Hi Jack,
Wow, thank you for your detailed answer. You saved me a big potential headache!
Matty
+1, poor strategy and I agree on Jack's rationale.
Thank you, yes I now have been educated! :-)
Excellent thank you for sharing your knowledge!
Matty
Boot iMac and Macbook from same extenal SSD
