UMS stopped working after power outage!

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thaMANSTA
Posts: 1
Joined: Wed Sep 02, 2015 5:39 am

UMS stopped working after power outage!

Post by thaMANSTA » Wed Sep 02, 2015 5:54 am

Hey everyone,

I encountered a very strange issue this weekend, with some pretty non-intuitive symptoms, so I figured I would point them out, as they should probably be documented, or at least give some sort of error or notification to the user.

My setup consists of an Ubuntu fileserver, which is NFS-mounted by a Windows 7 desktop machine running UMS. I mostly use my PS3 to play the content.

We had a power outage this weekend, and afterwards when the power came back, I was experiencing strange issues with playback on my PS3:
- When opening a folder, the items in the folder would appear, then duplicates of each of them would appear, then the original items would dissappear.
- Trying to play ANY recently added items would not work, the PS3 giving the error "The content cannot be played". Older files from before the outage worked fine.
- When opening many folders, even the ##TRANSCODE## folder, the PS3 was saying "No items". Very strange.
- I could play the content from other DLNA media players, e.g. on my phone, etc.
- There didn't seem to be any errors indicating what was going on in the UMS debug log.

In the end, I noticed that when the Windows machine running UMS had rebooted after the power outage, the clock was reset (probably a dead motherboard battery). When I updated my system clock via NTP, everything started working normally. The clock being wrong on the UMS Windows machine somehow completely confused the communication between UMS and the PS3.

In order to avoid this, perhaps UMS should verify the system clock of the host machine, and compare it via an NTP-type lookup? It could then warn users that their clock is set incorrectly, and this can cause problems with streaming to some devices.

Anyway, just wanted to give you a heads-up as this was a pretty obtuse error, and the cause isn't readily obvious.

Love UMS, great work guys!

Nadahar
Posts: 1254
Joined: Tue Jun 09, 2015 5:57 pm

Re: UMS stopped working after power outage!

Post by Nadahar » Thu Sep 03, 2015 8:23 am

Thank you for the tip. I've created a case for the issue here: https://github.com/UniversalMediaServer ... r/pull/661

Nadahar
Posts: 1254
Joined: Tue Jun 09, 2015 5:57 pm

Re: UMS stopped working after power outage!

Post by Nadahar » Fri Sep 04, 2015 3:57 pm

I'd like to ask you thaMansta if you could assist us in finding out a little bit more about the issue. I'd like to know two things:
  • How big a time difference does it take to create the problem? Is a few minutes enough, or does it take hours, days... even years? Since your clock was reset, I guessing it was more than just a little off.
  • Once the approximate time difference is estabilished, could you try changing the clock on the PS3 as well and see if that gives similar problems? The problem could possibly be because of the server <-> renderer communication, or something completely different like e.g. that the file timestamps are in the future.
I don't own a PS3 or any other suitable renderer to test this, and I mostly use software renderers on the same computer as the server when testing. That means my clocks are always in sync.

If anyone else has a suitable setup and want to test, please do so and report the results here. We just need to understand a little bit more about the cause of the problem to know how to address it. If anybody is able to replicate the problem, posting a trace log could also be useful: Go to the "Logs" tab and click "Create TRACE Logs" to restart UMS in trace mode. Try to browse and play files while the problem is there, and then click "Pack debug files" to create a zip file with the config files and log.

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