I'd be curious to know more about your solution before I do anything.
Firstly, are we talking about a purist music server, or the playing client? Or do you make one box perform both functions?
Regardless, it doesn't matter. The Raspberry Pi can do it all.
If you search for Raspberry Pi music server you'll find about 62 different varieties. Some are extraordinarily good (Volumio, Rune, Max2Play, et al).
I use a Pi3 running Raspbian (headless) to run Logitech Media Server, as I use Squeezeboxes. LMS does, however, have DLNA server, so you can connect any client you like (and I also use it as the video server and family general file server). This sits in the comms cupboard at the back of the house, as I refuse to have a whirring and vibrating hard disk in the listening room. Raspbian is the "official" Pi OS, however you can run any ARM distro you like on it.
You should be able to run your JRiver on a Pi.
https://www.google.com/url?sa=t&rct...opic=95578.0&usg=AOvVaw25s_sFUYFAqjOW8G9YVqfJ
Another really easy way to get up and running is to use PiCorePlayer - it is a combined Logitech Media Server and Squeezebox client. The guy who develops it is great. It's based on TinyCore linux (one gotcha - if you want to run it as a server, don't download the audio optimised version - that's for players only).
I also use PiCorePlayer as Squeeebox clients, also on Pi3 boards. All have Digi+ I2S digital output boards connected via the GPIO and digital out to decent DACS. They're capable of up to 192k and DSD. They sound great. Playing the same file, I can discern NO DIFFERENCE between this and the real Squeezeboxes (except the real Squeezeboxes aren't capable of 192k!).
The benefit of TinyCore (and hence PiCore) is that it is extraordinarily small, and runs completely from RAM. The OS / SD card is then run read-only, so that you can just power them off whenever you feel like it without any chance of corruption.
They're as cheap as chips.
Much to the disdain of some here, I have even siphoned some of the digital stream to a file and checksumed the results. Funnily enough, the resulting MD5 was identical,
proving there is no difference.
DM me if you want to know more. I'll post some pics.
Disclaimer: I've only been running the server for less than a year (since October/November last year), so no comment on long term reliability.