I'm re-using an existing key on a new system, new pool, etc.  I pulled the key from the last system, am I better off to just plug the usb stick into the system and boot just like it was, or should I redo my thumb drive with fresh files?  My concern is any pool data that may be on the thumbdrive.

Not entirely clear what you mean by pool in this context. btrfs cache pool is the most frequent use of that term lately, but perhaps you just mean the user shares ability to pool disks in the parity array.

 

You can use the existing key in a new system. It is just a question of whether or not there is anything from the old system you want to retain, such as disk assignments and other settings from the webUI.

By pool, I was referencing the pool of drives that make up my array.  I'm starting a completely new system,I don't want/need anything from the old system, just reusing the key and some of the hard drives, but for a completely new system.

I'll boot it up and see what happens, I can't screw anything up at this point:)

The upgrading to version 6 WIKI has a lot of information on how to do any upgrade and what files to copy over to do any upgrade without loss of data and setup information.  Here is a link to it:

 

    http://lime-technology.com/wiki/index.php/Upgrading_to_UnRAID_v6

 

 

If you aren't going to retain the disk assignments, then you must be very careful with how you reuse the disks if you want to keep any data already on them. If you add a disk to an array that already has parity unRAID will clear it.

I don't need any of the data on any of the discs, and it was running 6.1, so I didn't think the migration document was going to help.

 

Sounds like you don't want to keep anything from the old install so the only thing you need to keep is the keyfile. Just save the keyfile somewhere, format and prepare the usb stick just like a new install, and copy the keyfile back. That way you can be sure you start with a clean installation.

I would still make a copy of the original install before I wiped that Flash Drive clean.  (A copy will assure that you will never need any of the files from it.  Not making the copy will guarantee the converse!)