Hi I have two Primes and I’m trying to give Plex four tuners. How does plex decide the which tuner it will use? I had thought that it would use the tuner with the lowest IP address (or the one with the lower device ID) - but that doesn’t seem to be the case? is there a way to force it to prefer the tuners in order? device 1 tuner 1, then 2, then 3, THEN device 2’s tuners?
Don’t believe so. Plex seems to predetermine what tuner will be used in advance of a recording, don’t know how far in advance. If that tuner is busy when the recording tries to start the recording will typically fail. You also can’t tell Plex that it can only use specific tuners on a device. Once device is added Plex assumes it has exclusive access to all the tuners on the device. So if both of your Prime devices are added to Plex it will assume it can use all 6 tuners, so if 2 tuners are in use by other devices in your home and Plex tries to record something using one of them you will more than likely miss that recording. Hopefully this feature is in the work with Plex development but believe they are still trying to bug fix before adding new features.
It’s something they need to prioritise for a fix in my mind. At the moment you either record TV or watch live. You can’t do both for fear of failed recordings
This is one of those “What were the Dev’s thinking” type moments. The actual tuner should never be pre-assigned because Plex DVR does not have exclusive use of the tuners. It should only keep a count of how many tuners have access to a channel network and not by number either. CBS on an over the air channel will most likely have a different channel number then what is on the cable lineup.
The tuner to use of course should be checked at the time of the recording. IE give me the first available tuner with this channel on the lineup. This is important because a person could have both Over the air and Cable Card lineups which are different. Over the air lineups will almost always have a small subset of the cable channels so it should get priority of use when ever a channel is on that tuner BUT should be user configurable non-the-less because a person could be on the fringe of reception and might only want to use the Over the air as a backup/2nd source.
I’m sure they will get it sorted out but still… 
Carlo
I struggled with basically the same issue. I found a work around (hack) to change the priority of my tuners.
