I got an alert that the root disk on my BC server was filling up and discovered it was the bluecherry.log file. It grew to nearly 9GB before the alert fired.
Anyway it's just full of "E(RTSP): accept() failed: Too many open files" ... and the client can't connect to anything.
I bounced the service and it's working again. I last restarted it at about 9am today.
The only thing that might be different about today is I was flipping cables around in a patch panel, so the server would have its connections to the cameras severed at some point, but I would hope that couldn't cause a failure like this.