Debugging problems at moderate size (14-16 participants)

Hi,

apologies if I chose the wrong room. I have deployed and used Jitsi Meet successfully in our tiny group of researchers, using it with conferences of up to 7 people. Recently our group grew to 16 and I upgraded the server to 4 CPUs with 8 Gb of RAM. Unfortunately, the videoconference experience seems unusable for this tiny group.

The symptoms we are experiencing are

  • Some participants have no video feed from no participant.
  • Unable to share screen, or sharing flashes and then disappears from the video stream.
  • Participants drop from the conference.

I have monitored the server during the conference and it was always well below 30% load. Computers, OTOH, were close to 90-100% CPU. Everyone was using Chrome or a variant of Chromium, such as Edge.

At some point we gave up and migrated our conference to meet.jit.si and the experience was identical.

After 10 minutes we gave up again and used Google Meet, which was fine, so it seems that it might not be completely a bandwidth issue from the users point of view.

I would like to stick to jitsi and am trying to debug what is the problem. It seems it is not our setup. I see no warnings on the jvb.log. Just over 2000 lines in our 15 minutes of attempts. On the jicofo.log I see about 30 entries like the one below, which seems to explain or identify cases of students dropping from the videoconference randomly.

Jicofo 2020-10-07 10:00:15.544 INFO: [32] 
org.jitsi.jicofo.JitsiMeetConferenceImpl.log() Terminating 
Participant[quinfoglounge@conference.***.***.***/533230c8]@1647341300, 
reason: null, send st: false

I have a minimal configuration, with one instance of jitsi-videobridge, one instance of coturn and jicofo, all configured by Debian, with additional configuration by me to add LDAP authentication for room creation – participants enter as guests.

Is there a way to debug what are the problems? Or, alternatively, is there a different configuration that solves the performance issues? I would be ok with a Google Meet presentation model where the presenter always has a decent video resolution, and the rest have a medium or low resolution, enough for a grid view of 4x4.