I was surprised to see how full drive 3 has become and it looks like I should stop loading in any more and perhaps should even move some files across to the other drives.
But maybe I’m concerned unnecessarily because they are read only drives?
Roon does not write to your files so as you say these drives are Read Only so I am not sure why they would limit.
My drives are pretty full ( I have 3 drives 2 Audio, 1 Video), I bought a 5TB USB drive to split off some less used files so my main 4Tb drive has 700 Gb space. I never notice any issues.
I would have said as long as the OS drive that Roon uses to store its database has enough room I can’t see any problem. I use a NUC with a 256 SSD OS drive so its literally < 5% full. It’s hard to find < 256GB SSD these days
On a 5% free basis I have filled up Roon 3 as much as is sensible and each of the other two would be at that 5% or so level at 350gb free so I have some, but not a lot, of space there to fill.
Of course the other alternative is to free up space with deletions - the DSD files are huge and my ears really do nor detect any difference to other hi-rez. Maybe even convert them to 48/24 as those files sound as good as any others to me and the CD 44/16 can be pretty impressive anyway - it all gets back to the skill of the recording engineers IMHO. And yes, they do seem to make more effort with hi-rez recording and, to me, that is why some sound so good.
But of course the bottom line is that I really do have more than enough music anyway and am getting tired of editing.