Plex Server Hard Freezes CustoMac

[tanderson92]

I'm also asking in the Plex forums, but asking here in case there's anything I can learn. The 2015 CustoMac in my build signature on OS 11.7.6 has been locking up a lot recently. The problem is it's when I'm using Plex Server on the CustoMac to watch programming from the other side of the world. When I can get my wife to access the box, the power is on but nothing displays on the monitor. The box isn't accessible via TeamViewer or from my wife's Macbook Pro. The only recourse seems to be to power cycle it. I'm suspecting Plex because the machine spends months online with no troubles, but after using Plex will fairly reliably freeze up either in the middle of playback or after I've finished watching the current program. By the time I get back home, the device has generally been restarted 3-5 times, depending on how much free time I've had to watch from abroad.

I'm looking for advice here how to troubleshoot it. Usually by the time I get home it's been reset and days have gone by without an issue. It's currently locked up right now, and I should be home on the 30th. I'm planning to leave it locked up until I get home. Once I restart it, where should I be looking for errors that caused the system to freeze? I've poked around the Console and Plex logs but haven't seen anything that looks like a cause. I'm wondering if the hardware is starting to fail and not being able to transcode content on the fly is what's overloading it. Anyway I appreciate any advice to help me troubleshoot these lockups. I'm looking into moving Plex Media Server to my NAS which might be a more reliable option.

 

[c-o-pr]

When you write "transcode" that points to the distinguishing feature of a Plex workload: high CPU might cause a thermal edge case and freeze.

Try running Handbrake as a test case.

More ideas:

• There isn't a log for precisely such failure modes, but a tool like iStat Menus can display a history for various thermal sensors that might be informative.

• If you are overclocking your kit, review that config.

• A failing hard drive is a culprit. Try making a copy of whatever vid that caused a hang when played.

Carbon Copy Cloner will report drive errors for a backup task, if any have occurred on the tasks volumes since the last boot. You could run full drive backups and see if it complains.

• A RAM problem. Running memtest86 is worthwhile.

• I don't know if Plex transcode engages VDA / Quicksync Video Toolbox acceleration to apply GPU HW codec to transcode. You can search web for more info on this. If it does, this could implicate the GPU in the problem. But this would be an unusual failure mode.

• Is the screen off because of sleep? Disable display sleep to see clues.

• Sleep related config is a common cause of hack glitches. See Dortania Guide on sleep / power.

- Resetting macOS power management config might be helpful, via pmset command.

- There's a command called caffeinate that might be useful to prevent sleep.

- OpenCore NVMeFix kext deals with edge cases of NVMe drive power management. This might be relevant. I haven't seen the precise workarounds documented in detail (maybe there's a writeup in the kext source code). But it won't hurt to add this kext to your hack config as a hail mary.

• Running a scan for unwanted system agents might be worthwhile: See Malwarebytes and Etrecheck.

 

[pastrychef]

Is transcoding necessary? Even $25 Firesticks can play most content without the need for transcoding.

Your CPU doesn't have Quick Sync so transcoding would probably put a decent load on your CPU... Still, it should not cause freezes... Make sure the CPU cooler is working correctly.

If transcoding is not necessary, consider switching to something more efficient to run your Plex Server. Raspberry Pis can run it very well.

 

[tanderson92]

Is transcoding necessary? Even $25 Firesticks can play most content without the need for transcoding.

Your CPU doesn't have Quick Sync so transcoding would probably put a decent load on your CPU... Still, it should not cause freezes... Make sure the CPU cooler is working correctly.

If transcoding is not necessary, consider switching to something more efficient to run your Plex Server. Raspberry Pis can run it very well.

It isn't necessary for the playback capability but for the bandwidth. I'm watching these on hotel wifi or sometimes cellular data, and I've found it works much better to have items transcoded for playback.

 

[tanderson92]

When you write "transcode" that points to the distinguishing feature of a Plex workload: high CPU might cause a thermal edge case and freeze.

Try running Handbrake as a test case.

More ideas:

• There isn't a log for precisely such failure modes, but a tool like iStat Menus can display a history for various thermal sensors that might be informative.

• If you are overclocking your kit, review that config.

• A failing hard drive is a culprit. Try making a copy of whatever vid that caused a hang when played.

Carbon Copy Cloner will report drive errors for a backup task, if any have occurred on the tasks volumes since the last boot. You could run full drive backups and see if it complains.

• A RAM problem. Running memtest86 is worthwhile.

• I don't know if Plex transcode engages VDA / Quicksync Video Toolbox acceleration to apply GPU HW codec to transcode. You can search web for more info on this. If it does, this could implicate the GPU in the problem. But this would be an unusual failure mode.

• Is the screen off because of sleep? Disable display sleep to see clues.

• Sleep related config is a common cause of hack glitches. See Dortania Guide on sleep / power.

- Resetting macOS power management config might be helpful, via pmset command.

- There's a command called caffeinate that might be useful to prevent sleep.

- OpenCore NVMeFix kext deals with edge cases of NVMe drive power management. This might be relevant. I haven't seen the precise workarounds documented in detail (maybe there's a writeup in the kext source code). But it won't hurt to add this kext to your hack config as a hail mary.

• Running a scan for unwanted system agents might be worthwhile: See Malwarebytes and Etrecheck.

Thanks for the reply and many suggestions. I'll be working through them when I get back to the machine and can work on it more consistently. In the meantime the logs show that the failure time seems to always be during the daily credits detection job, so I've disabled that for now to see if it's the culprit. I'm leaning more towards one of the issues you mentioned because this has happened at all times of the day and not just during the 02:00 daily credits run. At least I have some ideas to help me start troubleshooting. I've thought about pre-transcoding the whole library (I think Plex allows this) so that it doesn't fail during remote playback when I need it most.

 

[pastrychef]

It isn't necessary for the playback capability but for the bandwidth. I'm watching these on hotel wifi or sometimes cellular data, and I've found it works much better to have items transcoded for playback.

Ah. Then it's probably a good idea to go to a system that has hardware H.264 and H.265 encode/decode capabilities.