There is a new posting/review of Roon + QNAP and large libraries over on Audiophile Style entitled:
Running a Large Roon Library on a QNAP TVS-872XT
I have a similar experience to the reviewer, however, I am Synology-based.
My Synology DS-3617xs:
Intel Xeon D-1527 4 core 2.2.Ghz 32GB RAM 10Gb Ethernet
I also have a large local library with lots of HiRez files:
11K+ Albums 165K+ Tracks ~3K+ Tidal albums
When freshly booted, my NAS is snappy and performs well running Roon. Overtime, performance degrades - playback is fine but searching, pulling up info, etc… all things UI-related. I suspect a memory leak. Regular reboots isn’t a good solution as my NAS does other things as well which don’t like to be interrupted. I believe that Roon on a NAS is an infrequent deployment mode for Roon, and perhaps it doesn’t get as much engineering attention as other deployment modes. I love Roon, and am hopeful that one day a fix will appear. Especially given that running Roon on a NAS is really an ideal deployment mode.