Xen Tools on FreeNAS

Is there a way to install XenTools in a FreeNAS VM?

I think there are XenTools in the FreeBSD package repository, but I really recommend that FreeNAS has direct access to the drives in order for it to work properly.

I agree. I’m setting up FreeNAS in Xen Server to play around and maybe as a backup FreeNAS box.
I currently have a FreeNAS box that has direct access to the drive and is the only thing on it. I also have a Dell R520 with a PERC 710 mini that does not have the capability to be in IT mode to pass the drives through to the OS, so I have XCP-Ng on it. What would you suggest for a good backup option on this machine to backup the FreeNAS server to it?

For FreeNAS you only need to back up the config and encryption keys.