Making an M1 External Boot SSD in 20 Minutes...

[Mac... nificent]

so TB3 is from a HW standpoint much easier to setup this way for booting, do I understand it correctly? Then TB3 enclosure and a fitting M.2 SSD should do it...?

Correct. You’ll have much better luck using TB3. I originally used a Inland 1TB PCIe NVMe M.2 2280 SSD with a Trebleet TB3 enclosure on a recommendation from the Apple site that worked great. I like it much more than the Western Digital black SSD. I ran out of room sooner than expected with the 1TB version, so I upgraded to a 2TB version of the Inland NVMe SSD (https://www.amazon.com/Inland-Premium-M-2-2280-Internal/dp/B07RCM6DXK).

Both Inland SSDs have been fast and rock solid. The enclosure works great and doesn't even get warm. Seeing how Apple will be using M chips from here on out, I saw it as a worthy investment to buy the best from the beginning. the enclosure comes with a TB3 cable also. (do not use a USB-C cable, they do not work correctly at this time).

2 in 1 Thunderbolt 3 / USB 3.2 SSD Enclosure | up to 2700 MB/s in Thunderbolt 3 Mode or up to 900 MB/s in USB 3.2 Mode

2 in 1 Thunderbolt 3 / USB 3.2 SSD Enclosure | up to 2700 MB/s in Thunderbolt 3 Mode or up to 900 MB/s in USB 3.2 Mode

www.amazon.com

 

[TheRes0rector36]

did you have any issue with SSD's speeds slowing down after turning into an external boot drive? mine went from

APFS 1924 write / 2633 read

to

APFS 609 write / 349 read

according to black magic speedtest

 

[yellowhelicopter]

Great method, but how well M1 Macs work with MacOS on external drive in general?

I read about problems with unexpected disconnections of external USB drives in other thread. One thing is if disconnected is just a storage drive, but random disconnections of a MacOS drive is unacceptable.

 

[Leon1das]

Great method, but how well M1 Macs work with MacOS on external drive in general?

I read about problems with unexpected disconnections of external USB drives in other thread. One thing is if disconnected is just a storage drive, but random disconnections of a MacOS drive is unacceptable.

For me it works wonderful with no disconnections..

BS 12.2.2 installed both on my M1 MBP and external SSD Samsung T7

 

[Snowii]

How does the experience between the internal and external installations compare? Any noticeable disadvantages in using the external T7 boot?

 

[Mike Boreham]

How does the experience between the internal and external installations compare? Any noticeable disadvantages in using the external T7 boot?

Three differences I am aware of:
1. Slower than internal, but probably not noticeable unless you measure it (IMO).
2. TRIM not supported, but may not matter with onboard Garbage Collection.
3. SMART will not be fully supported. In System Report it shows SMART as verified, but if you try and use a specialist SMART app like DriveDX it needs the SAT SMART driver to access USB externals.

Note that Thunderbolt3 externals avoid all three, although may still be slightly slower.

 

[Apple_Robert]

I just made an external boot drive using my Samsung T5. It worked the first try.

1) Booted into Recovery
2) Erased the T5 and formatted as APFS
3) While in Recovery, installed Big Sur on the T5
4) Once install finished and the T5 rebooted, I used Migration Assistant to transfer all the settings from the M1 to the T5.

 

[Mike Boreham]

I just made an external boot drive using my Samsung T5. It worked the first try.

1) Booted into Recovery
2) Erased the T5 and formatted as APFS
3) While in Recovery, installed Big Sur on the T5
4) Once install finished and the T5 rebooted, I used Migration Assistant to transfer all the settings from the M1 to the T5.

I have successfull done similar very recently. The difference for me was that I used Setup Assistant at the end of the install instead of Migration Assistant after booting as you did. How did you handle user accounts?

To boot the external you must have created a User account which would be UUID 501. If you used the same user name as the one you were migrating MA offers to overwrite the one you created so that it is still UUID 501, but this has been a problem for me in the past, so I always use Setup Assistant. This process may have become more reliable since I last did it.

 

[Apple_Robert]

I have successfull done similar very recently. The difference for me was that I used Setup Assistant at the end of the install instead of Migration Assistant after booting as you did. How did you handle user accounts?

To boot the external you must have created a User account which would be UUID 501. If you used the same user name as the one you were migrating MA offers to overwrite the one you created so that it is still UUID 501, but this has been a problem for me in the past, so I always use Setup Assistant. This process may have become more reliable since I last did it.

I did set up the same user on the external drive.

 

[Mike Boreham]

I did set up the same user on the external drive.

So Migration Assistant asked if you wanted to overwrite user of the same name and successfully did so?

 

[Apple_Robert]

So Migration Assistant asked if you wanted to overwrite user of the same name and successfully did so?

No, I don't believe I was asked to overwrite user of the same name.

 

[Ektachrome]

Love that this seems to be working, and thanks for the procedure!

A couple of questions for people running this way -

- Does running the OS from an external boot drive also mean that any excessive SSD writing (re: the dreaded TBW issue) is also transferred to the external SSD? Has anyone seen whether then internal SSD still has excessive kernel task writes or is it all on the external after this?

- Are you able to have FileVault ON when running the OS from an external SSD?

 

[Mike Boreham]

No, I don't believe I was asked to overwrite user of the same name.

Interesting...I haven't done it for a while, maybe things have changed. Will give it a test.

 

[Mac... nificent]

How does the experience between the internal and external installations compare?

I'm using an NVMe SSD and there are no differences at all in the experience.

 

[Mac... nificent]

Does running the OS from an external boot drive also mean that any excessive SSD writing (re: the dreaded TBW issue) is also transferred to the external SSD?

No excessive writing here, and I'm monitoring it.

 

[Mike Boreham]

I'm using an NVMe SSD and there are no differences at all in the experience.

Is that with the Thunderbolt enclosure you described in post #51?

 

[Mr Screech]

Does it make sense to use timemachine for external bootdrives?
Or won't this work during recovery?

I just made a timemachine backup and it made a backup of both the internal and external drive. Is this normal behavior?

 

[Snowii]

No excessive writing here, and I'm monitoring it.

that's good to know but have you had any to start with? have you done any of the mitigating steps discussed in the other threads?

I am considering using external ssd for LR work as a solution for the excessive swapping - interesting would be to know whether using external boot completely eliminates this RAM-SSD swapping relationship due to some "hardwired" OS pathways of how to move data around (and not do it when external drive is used)...

 

[Mike Boreham]

Does it make sense to use timemachine for external bootdrives?
Or won't this work during recovery?

I just made a timemachine backup and it made a backup of both the internal and external drive. Is this normal behavior?

Normally by default Time Machine automatically excludes external drives, but you can remove them from the exclusion list so that they are backed up.

I don't believe there is any harm in having TM backup both if you have the capacity.

 

[Ektachrome]

that's good to know but have you had any to start with? have you done any of the mitigating steps discussed in the other threads?

I am considering using external ssd for LR work as a solution for the excessive swapping - interesting would be to know whether using external boot completely eliminates this RAM-SSD swapping relationship due to some "hardwired" OS pathways of how to move data around (and not do it when external drive is used)...

This is exactly why I would be considering this also, so would be really helpful to know, if you had the issue to begin with, or use Adobe Lightroom, that is.

If you did/do and the internal SSD continues to experience excessive SSD swapping while running LR from an external boot SSD it would perhaps indicate this behaviour is due to the way the M1 SOC works(?), if any excessive SSD swapping switches to the external boot drive, this is less likely to be the case, to my mind.

Also, importantly, even if it did, you would not be trashing a non-user replaceable SSD, just one which is easily replaced externally, at least until the issue is solved by Apple/Adobe.

 

[Ektachrome]

I have successfull done similar very recently. The difference for me was that I used Setup Assistant at the end of the install instead of Migration Assistant after booting as you did. How did you handle user accounts?

To boot the external you must have created a User account which would be UUID 501. If you used the same user name as the one you were migrating MA offers to overwrite the one you created so that it is still UUID 501, but this has been a problem for me in the past, so I always use Setup Assistant. This process may have become more reliable since I last did it.

Does this imply that you can't have the same User Account simultaneously on an external boot drive and the internal drive, or have I misinterpreted?

I'd like to mirror the accounts external/internal, if possible, in order to switch between the two as needed.

 

[Mike Boreham]

Does this imply that you can't have the same User Account simultaneously on an external boot drive and the internal drive, or have I misinterpreted?

I'd like to mirror the accounts external/internal, if possible, in order to switch between the two as needed.

No that is OK. As far as MA is concerned the external and internal are different computers.

 

[Ektachrome]

No that is OK. As far as MA is concerned the external and internal are different computers.

Ah, OK. Thanks.

 

[Spudlicious]

A question for those who have successfully created an external boot drive, and I hope it doesn't make me look too dumb. If CCC is then used to clone the internal drive to the external, and let's assume it's TB3, does the external remain bootable? I'm thinking ahead to when I possibly update my iMac but would like to try it with my M1.

 

[Mr Screech]

A question for those who have successfully created an external boot drive, and I hope it doesn't make me look too dumb. If CCC is then used to clone the internal drive to the external, and let's assume it's TB3, does the external remain bootable? I'm thinking ahead to when I possibly update my iMac but would like to try it with my M1.

I've just tried this hoping it would work, but I couldn't make the TB3 drive bootable after cloning.