Tonight I'm in the process of my second mosaic (loving it clearly) , but unfortunately ran into the "too many open files" issue with the offline solver again. Using the latest Kstars and INDI drivers. Might this be a problem in my astrometry installation?
You can check /proc/xxx/fd to get a list of running file handles per process pid (xxx). I believe your system should start to complain about a process and reject its open requests around 4K handles. If there is a leak somewhere in the code, you might be able to spot which pid has that many handle references, and thus find in which tool the problem is located. But it might just say "well it's indiserver", in which case a more contrived configuration may be needed to separate processes.