Booting from external hard drive Macbook Pro 2017. Is it a good idea?

[jandrocamus]

I own a 2012 macbook pro and recently got a 2017 macbook pro from my family with only 128G hard drive.

I am planning to take my old macbook's 500G SSD hard drive and always boot from there on the new 2017 macbook. I'd be using this enclosure/cable.

Is this a good idea? Would I be running into performance or any other issues?

 

[Juicy Box]

I have used external boot drives a lot in the past, and there shouldn't be any issues, other than the potential of accidently unplugging the drive, which being a laptop vs a desktop, might have a higher chance of happening.

As for performance, the newer internal SSD would probably be faster, but the external one should still be pretty fast.

External drives are fine as a boot drive. I have created boot drives from iPods before, and other than them being slower than the internal drive, they were reliable as boot drives.

 

[Fishrrman]

"Is this a good idea? Would I be running into performance or any other issues?"

Let me begin by saying that I am a fan of "external booting", but on DESKTOP Macs.
I've been booting and running my 2012 Mac Mini from a USB3 docking station since the day I took it out of the box in January 2013. Runs great.

HOWEVER...
I DO NOT believe that what you propose above would work that well.

First off, the internal SSD on the 2017 MBP is ORDERS OF MAGNITUDE faster than ANY external drive (even SSD) is going to be.
If you don't believe me, download the app "AJA System Test Lite" and run it yourself on the internal drive, and then on your external drive. Then post your results here.

This doesn't mean you can't connect and use the external SSD.
BUT...
I would set up the internal SSD with your OS, apps, and account.
If you have "large libraries" of stuff (movies, music, pics), you can use the external SSD to store them.

This way, you need only connect the external when necessary.
It's going to make things much easier in actual usage.

With a laptop, it's far too easy to jiggle the connecting cable -- even a momentary "disconnect" could crash the system (if you're booted from an external drive).
"Well, that could happen anyway", you might reply, "even if I'm booted from the internal drive".
Sure... but if it's just a (non-booted) external drive, all you'll get is a "this drive was improperly disconnected" message, and the OS will "keep on going".