The backup server is just my old server, in case the new one goes down. It is also the only one that houses actual server class hardware. (Dual XEON MB.)
The file server/gateway runs Koozali SMEServer (A CentOS derivative that has a dedicated Server/Gateway mode.)
This server has 17TB of network storage. (I am not using RAID of any kind but have redundant copies of all the stored data.)
NextPVR is a PLEX-like software that supports streaming from my HDHomerun network tuners. The standalone Windows version has a local server. I am using the Linux server backend instead of local servers. It can also transcode on-the-fly if there is a need.
Using the Kodi NextPVR addon on either Windows or Android, I can get guide updates from the backend and pause/record live cable TV. (Linux support is broken until after the next Kodi stable update.) This server is running Ubuntu with a Desktop.
Both servers are using new hardware, one Intel and one AMD.