MP 7,1 PCIe bootable drive and Internal SSD

[assisterah]

I'm planning to config a MP 7,1 with no more than 1TB storage and use the external PCIE SSD as my bootable main OS drive.

I've read it should work and see plenty of folks here actually preferred this way to save cost(going with 256GB).

But my question is:

1. What happens to the internal SSD? Can I erase the internal SSD and use it as a storage/scratch drive?

2. is there any catch/downside on using PICe drive as the main OS drive?

 

[LeonPro]

You can repurpose the Apple SSD, but I wouldn't erase it from factory. I did a similar thing. I purchased 4TB Apple SSD and then Samsung 970 Evo Plus 1TB for my Boot drive.

All you need to do is enable External Booting at the Startup Security Utility before installing the OS in the PCIE. The problem with you erase the Apple SSD, it doesn't allow you to go back into the Startup Security Utility. No matter what password you enter, it won't accept it. You can blame the T2 security chip behaviour and I don't know if this is a bug. I was talking to Apple support about it and the only way to get this log in back is to do a Restore on the computer itself and install the OS back into the Apple SSD.

My suggestion is to use the Apple SSD as your boot and apps, and just install PCIe SSD drives for everything else.

 

[bernuli]

I'm planning to config a MP 7,1 with no more than 1TB storage and use the external PCIE SSD as my bootable main OS drive.

I've read it should work and see plenty of folks here actually preferred this way to save cost(going with 256GB).

But my question is:

1. What happens to the internal SSD? Can I erase the internal SSD and use it as a storage/scratch drive?

2. is there any catch/downside on using PICe drive as the main OS drive?

I would leave the internal drive as is. Add another drive of your choosing and move your home directory to the added drive.