[mythtv-users] Randomly crashing Mythtv combined backend and frontend

[Bill Meek]

On 05/18/2013 12:53 PM, Matthias wrote:
> Am 18.05.2013 19:43, schrieb Stephen Tan:
>> Hi list
>>
>> I'm remotely administering a Mythtv system for some friends and we are getting some very frustrating behaviour from the system.
>>
>> Setup:
>> We have 2 systems. One which is the Master mythbackend and Frontend, and a secondary backend box ( which also is a Frontend ). The main box
>> has 2 x dvb-s cards which get Freesat  and the backend box has 2 x dvb-t cards which get Freeview.
>> The distribution being run is Debian 7.0 Wheezy.
>> We are running 0.26-fixes compiled from source.
>>
>> Behaviour: Random crashes at any time of the day which kills the frontend as well. We were not getting much meaningful logging information on
>> the problem, so I have re-compiled with --profile to get some debugging information and we are now running debugging in order to try and get
>> some meaningful information about the cause of the crashes
>>
>> So far, we haven't had a crash, but the logs are full of the following types of errors:
>>
>> 2013-05-18 16:46:53.704140 I [14630/14821] DVBRead mpeg/pespacket.cpp:161 (VerifyCRC) - PESPacket: Failed CRC check 0xe3967750 != 0xd67980d0
>> for StreamID = 0x82
>> 2013-05-18 16:46:53.704150 E [14630/14821] DVBRead mpeg/mpegstreamdata.cpp:948 (HandleTSTables) - PSIP packet failed CRC check. pid(0xc0)
>> type(0x82)
>>
>> Does anyone recognise these symptoms? It would help a great deal if you could share any fixes with us.
>>
>> One thing worth noting is that the system is now running at a high CPU load now with mythlogserver using a lot of CPU. Probably the Observer
>> effect is in action here.
>>
>> thanks in advance
>>
>> Stephen
>>
>>
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>> mythtv-users at mythtv.org
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> Hi Stephen,
>
> sorry no help regarding the crashes. But regarding the high load from mythlogserver, you might want to check the number of mythlogserver
> processes - there should be only one, and there are reports from several people that in certain conditions, several mythlogserver processes are
> started, leading to 100% CPU load...
>
> I have had this behaviour myself, and I have seen the frontend (local and remote) getting unresponsive due to the backend load. So maybe this is
> what you are observing.
>
> Killall mythlogserver in my case did bring the system back, so I did not have crashes in that sense.
>
> I have not been able to fix the mythlogserver problem, but since moving from back/frontend to just a headless backend + several frontends on
> other machines, I did not have the problem again.
>
> A healthy mythlogserver process should never cause much load, I would think.
>
> HTH, good luck,
>
> Matthias

Hi;

Good points ^^^. As long as you're building from source, take a look at this post:

     http://www.gossamer-threads.com/lists/mythtv/users/534986#534986

Sounds very similar to antgel's experience on the -users channel this morning. The
reason those two errors print is that -v siparser,record are set (respectively.) Or
you're using -v all. My experience has been that errors that require action will
print when using -v general (as opposed to debugging tools.)

I'd suggest to you as well, that you define "Random crashes". If you see matching faults in
/var/log/syslog especially with words like "segfault", then you can look for core files and use
gdb (which sounds like the direction you're going with your rebuild.) The user on IRC
reported not seeing any errors in syslog.

Watching the commits mailing list *strongly* suggests that in 0.27 mythlogserver will
be history.

-- 
Bill