How can I diagnose my Qubes issues? (mainly looking for logs regarding freezing, etc.)

Hello, all! I have had less than stellar luck getting responses leading to resolutions to Operating System glitches on these forums, despite some wonderful people who reach out to offer comments when they can. I think it may well be because the forum community is simply smaller than most OS forums at this time, and that’s understandable. But since I really want to use and help promote Qubes, and not give up on using it, but I am kind of banging my head against a wall with seemingly endless issues that I am not capable of even diagnosing, I either have to give up on it for now or to make a plan. And I hate giving up on things… So, here’s my question:

Would someone out there be able to let me know how I can view and understand the log files in Qubes? Then I should hopefully be able to get most of these issues at least identified and work to fix them myself if necessary. I think a big part of my confusion revolves around Xen. If I was just looking for Linux log files for fedora or debian, I can find a thousand articles around the web to assist, but I just don’t know where to look.

At this moment, I have two (I think separate) logs I am looking for:

  1. My Qubes install tends to simply freeze solid a couple times per day. I cannot predict when it will occur and I haven’t seen a clear pattern yet. But when this happens, not even the mouse or keyboard will do anything on screen, so I know that dom0 itself must be frozen. So, where would I look for a log to tell me what happened just before the freeze?

  2. I have very regular crashing or dying of pulseaudio microphone input (this is another topic I posted earlier 2 months ago but have no responses to). This must be a dom0-level issue with the audio because it won’t work in any VMs after that crash occurs. Again, where would I look for a log for pulse audio dying?

I really want to learn to fix my own computer’s issues if possible, as I imagine most people here tend to do (unless I am the exception to rule; I tend to have issues pop up with almost half the new actions I try to take using Qubes OS, so I assume that most users are savvy enough that they simply can solve these as they arise) and I am hoping this will be a good step toward that so at least I know what to tackle. Can anyone take some time to tell me about logs in Qubes?? I am using KDE in Qubes if that is relevant. Are logs placed in the same spot regardless of Desktop environment? It is appreciated.

This is simple, just run sudo journalctl -b -1 -r after you hard-reset your machine. This will give you journal logs of the last boot (-b -1 means boot -1), in reverse order ( -r means reverse). So you will be able to immediately see the last lines of the system log.

What if you try sys-audio, so you can simply restart that Qube when the crash happens?

I remembered that some Qubes Devs were working on reconnecting the vchan when one of the endpoint died, so it wouldn’t be necessary to restart all qubes whose audio_vm was sys-audio, when sys-audio was restarted.

I also had this problem and resolved it disabling the nouveau drivers (provided you have an nvidia gpu): Contents/ at master · Qubes-Community/Contents · GitHub

Listen to this guy. Avoid nvidia, I had all kinds of problems with the nouveau drivers. They would work fine on a computer with a normal bios, but once I switched to a different computer with libreboot, it wouldn’t behave. Grab a workstation AMD GPU and things should work.

Thanks so much for taking the time to send some ideas and explaining what the commands mean. I will try this. So I can continue building my knowledge here, is this command specific to Qubes (or Xen) or is this a standard Linux command?

Also, as for the sys-audio idea; I am not familiar with this. I may do some searching for that, because the audio issues are one of the real deal-breaker sorts of troubles I’m having since I need to use my microphones for videoconferencing and content creation regularly. I really appreciate the idea.

Also, thanks for ideas about the nvidia gpu. That makes sense and I have heard the nvidia drivers are a real issue frequently, but I am not using an nvidia card, actually (on a laptop with intel graphics). So my issue lies elsewhere, as far as the freezing goes. I will check the logs and see what I can find for that the next time it occurs.