[mythtv-users] Slave Backend requirements

[Michael Watson]

On 21/08/2013 11:07 PM, Michael T. Dean wrote:
> On 08/20/2013 10:34 PM, Michael Watson wrote:
>> I run my Frontends as SBE (with a configured Dummy Tuner) to assist 
>> with commercial detection, whilst I know I can use mythjobqueue to 
>> achieve this, with Mythjobqueue the SBE/Frontend will not shut down 
>> whilst not in use, mythjobqueue is great for a 24x7 system.
>
> I'm not sure what, specifically, you mean by this, but since Feb 2012 
> mythjobqueue only holds a blocking connection when it's actually 
> processing jobs, but changes to a non-blocking connection (which 
> allows master backend shutdown) when it's idle.  (This has been in 
> releases since 0.25.)
>
> http://www.gossamer-threads.com/lists/mythtv/commits/502795#502795
>
> So a mythjobqueue server won't prevent the master backend from 
> shutting down, unless it's actually running a job (which requires 
> master backend presence/availability).  And a mythjobqueue server will 
> take significantly less resources than a remote backend.
I would say that the difference in resource usage between the two is 
significant.  Yes there is a difference in resource usage between the two.
>
> If you're saying that the master backend won't send out a message 
> telling the mythjobqueue system to go to sleep, that's true, but then 
> again, that's only useful on a machine with tuners that the master 
> backend may decide to use at some time that the remote backend can't 
> predict.  On a machine that doesn't have tuners that may be needed at 
> some unknown point in the future, the machine can simply shut down 
> when it desires.  So, you could use the frontend idle shutdown 
> capability or mythshutdown to shut down the computer when idle.
>
> I don't know if mythfrontend's idle shutdown capability checks job 
> queue status, but I know mythshutdown does, so you may need to use 
> mythshutdown.

I found mythshutdown next to useless in a MBE/SBE scenario, it only 
returns "OK" when all tuners are idle (and not required in the near 
future), so a slave backend will not shutdown until the MBE's tuners are 
idle.  On a SBE/FE mythshutdown will allow the BE's to shutdown whilst 
watching a recording/video or listening to music - ie totally ignores 
the FE running on the same machine.
     In 0.25 and 0.26, I found the Frontend Idle detection incapable of 
shutting down the FE, but I do recall this changed during the 0.26 cycle 
(allowing the execution of a script when FE is idle), but have not 
returned to it, as I have developed an idle detection script that takes 
into account what the local FE and BE are doing.
     Using myth tools alone, I could not get a FE or SBE/FE machine to 
shutdown when it is idle but stay active when its in use, mythwelcome 
requires you to exit mythfrontend before it will shutdown (totally 
useless in my view), the Mythfrontend idle detection (last time I looked 
at it) only detected idleness, didn't do anything about it, and a SBE 
will shutdown whilst its local FE is in use.

>
> Mike
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