[mythtvnz] [Mythtv] How to view the backend logs

[Karl]

In case you are not using any *buntu distro, then you can find the log file
by using the find in the terminal with the below command:

find / -iname '*mythbackend.log*' 2> /dev/null

The 2> /dev/null points stderr to a null file so that it does not clutter
any error output to the terminal.

Stephen has covered a lot of detail to help pinpoint the issue. But pasting
the output for us to check is a good suggestion.

On 26 May 2018 at 23:08, Stephen Worthington <stephen_agent at jsw.gen.nz>
wrote:

> On Sat, 26 May 2018 18:36:16 +1200, you wrote:
>
> >My mythtv system is having issues. If I try to use it it will play for
> >about 30 seconds to a minute then says:
> >"Could not connect to master backend MythContext Could not connect to
> >the master backend server. Is it running? is the IP Address set for it
> >in myth-setup correct?"
> >
> >Obviously the IP Address is correct or how else does it play 30-60
> >seconds of live TV before breaking.
> >
> >I seem to be able to do this twice before it says all tuners are
> >currently busy, and I also can't see any of my recordings.
> >
> >I'm hoping that if I can see the backend logs it might give me a clue
> >as to what is going on. However I can't seem to find out how to view
> >them.
> >
> >A little background:
> >This system has been working for years, however around the time of the
> >royal wedding we noticed that new recording showed red spinners on
> >them and they never stopped (they still have them) Usually they have
> >green spinners while recording and then red for a short period after.
> >Then this morning my wife noticed edge tv wasn't working (a blank
> >screen if you tried to watch it) so she closed mythtv did the ubuntu
> >updates (hadn't been done for ages) and restarted the machine. That
> >didn't fix the problem so she came to ask me for help. I ran the
> >backend setup and tried to do a rescan on the channels but the scan
> >didn't work. So I googled it and found out this can happen if the
> >backend is still running (the back end setup program should stop it
> >but obviously had failed to do so. I stopped the backend from the
> >commandline which took ages, and then ran the channel scan which
> >worked fine. Now the edge channel was on a different number, it did
> >work but only for 30 seconds, then showed the message as per above. So
> >I tried other channels and they all have the same problem.
> >
> >My guess is that the backend is crashing but I need to look at the
> >logs to know why, and that does not seem to be documented.
> >https://www.mythtv.org/wiki/Logging seems very complicated and doesn't
> >actually tell you how to see the logs assuming a default config.
>
> On Ubuntu, the log files are in /var/log/mythtv.  The backend log is
> "mythbackend.log".  You may or may not have enough information in the
> log file to work out what the problem is.  What version of Ubuntu and
> MythTV are you using?  In recent versions, you can add extra logging
> options to the mythbackend command line by creating a file like this:
>
> root at mypvr:/etc/mythtv# cat additional.args
> #ADDITIONAL_ARGS=-v all --loglevel debug
> ADDITIONAL_ARGS=-v record,dvbcam
>
> You create a file "additional.args" in the /etc/mythtv directory, and
> put in a line which is a Bash variable assignment statement assigning
> your extra command line arguments to the variable "ADDITIONAL_ARGS".
> The first line in my file (commented out with a # at the start) would
> turn on all possible logging.  That is enough to slow down the
> operation of mythbackend unless you have a fast PC and the log file is
> going to a fast SSD.  But it will make sure that every possible
> message is logged.  The second line is the one I run with normally.
> The option you probably want is what I use there: "-v record", which
> tells mythbackend to log extra messages about how it makes recordings,
> including its interaction with the tuners.
>
> When you change the additional.args file, you need to restart
> mythbackend to get it to see the new command line arguments:
>
> systemctl restart mythtv-backend
>
> There is also an ability to change the logging at run time.  To do
> that, you run a second copy of mythbackend with the special command
> line options that change the logging.  The second copy of mythbackend
> finds the first copy and sends the new commands to it, then shuts
> down.  There are two options you use for this:
>
> --setverbose
> --setloglevel
>
> The --setverbose option allows you change the options set for verbose
> output, so you would do:
>
> mythbackend --setverbose record
>
> to do the same as the -v record option in the additional.args file. To
> turn off the record option, you would do:
>
> mythbackend --setverbose norecord
>
> To change the overall log level, you use:
>
> mythbackend --setloglevel debug
>
> which would set the logging level to "debug".  To reduce the logging
> again, you would do:
>
> mythbackend --setloglevel info
>
> which turns off the debug level messages, setting the logging level to
> "info".
>
> These commands give you the mythbackend command line help:
>
> mythbackend --help
> mythbackend -v help
>
> Warning: If you mistype the mythbackend command and it does not have a
> valid --setloglevel or --setverbose option, you will get a second copy
> of mythbackend trying to run alongside the normal one.  That is not
> good.  So if that happens, do this:
>
> ps -ef | grep mythbackend
>
> to see which is the wrong one, and then kill the wrong one:
>
> kill <PID of wrong mythbackend>
>
> and if that does not work within a few seconds:
>
> kill -9 <PID of wrong mythbackend>
>
> You may need to run some of these commands as root or using sudo
> ("systemctl" and "kill" will need that).
>
> If you have a log that shows the problems, you can post a copy on
> http://pastebin.com for us to look at.
>
> What sort of setup do you have?  Is it a combined backend/frontend
> box?  Is it set up to allow external frontends, or not?  What sort of
> tuners are you using?
>
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