This has become more complex with increasingly popular hybrid drives that support USB4/Thunderbolt and fall back to USB 3.x.
SMART
Check its protocol support and expected maximum transfer rate, then whether it supports SMART indicators and Trims with APFS. Finally check its real-world performance.
Given that Thunderbolt SSDs are unusual and expensive, should you buy a USB4 model that claims to be compatible with Thunderbolt? Watch out for the traps.
PC users will get 20 Gbit/s and SMART health indicators from this new external SSD, but Mac users will only see half that speed and no SMART without reducing security.
If you want it to have full TRIM and SMART support, it’ll need to have an NVMe interface and a Thunderbolt connection.
Adds the ability to check some key SMART health indicators for Apple Fabric and PCIe SSDs.
There’s a big difference between the storage that’s available, and what’s advisable. Whether it’s affordable is another question.
Creating the external bootable SSD, downgrading security and allowing kexts, then trying to install a kext on an external drive which must be ejected.
Apple wants us to run our Macs at Full Security and not use third-party kernel extensions, but refuses to build S.M.A.R.T. access into USB in macOS.
It’s a simple and popular request: how is my Mac’s SSD ageing? How long is it likely to last? But macOS has no tool to offer, and 3rd party tools aren’t really ideal for M1 Macs still.
The Eclectic Light Company 