Cannot attach second USB drive to boot pool - ERROR NoneType object is not subscriptable

[remonv76]

Running in the same issue with 2 nvme drives, but haven’t upgraded yet to U1. Seems it is still not fixed. Is there a support ticket to fix the new error?

 

[funwithdickandjane]

Posting for anyone else coming in with this same error message when attempting to mirror their boot drive, upgrading to 13.0-U1 fixed the issue for me.I was able to successfully mirror my boot drive after the upgrade.

 

[MarcAurel]

I paid $10 for a 32GB M.2 drive that I use for boot .. on one of my older setups, I used a USB to SATA cable to power a 120GB SATA drive that I got for $10.
USB drives haven't been recommended for awhile now do to the increase of read/writes to the drive with newer versions of TrueNAS so there was a substantial increase in drives failing. You can still use your USB drive if you want .. but it's just not recommended

What if you set your System Dataset Pool to something else than the USB drive, will there still a lot of read/writes to the USB boot-pool?