[mythtv] distributed master/slaves configuration questions

[Joseph A. Caputo]

On Tuesday 07 October 2003 07:20 pm, Michael J. Hammel wrote:

[snip]

> 
> I'd like to set this box up as a MythTV master backend server and then
> set up a series of MiniMyth slaves throughout the house (in the long
> term I'll have to migrate to a much bigger server, but this box will do
> for now).  My goal is to have the slaves tell the server when to record
> and what to feed to the slave - including live TV if possible.  I have
> some questions on if/how this might be done.
> 
> 1. I take it that slaves require a slave backend configured and that it
> is the backends that talk to one another to get the master to feed the
> slave the video/audio.  The frontend only talks to the local backend. 
> Is this a correct view of the architecture?  As long as the master
> backend is running (the master frontend does not have to be running),
> recordings requested by slaves will be made and LiveTV can be fed to
> slaves.  Correct?

Wrong.  What it sounds like you want is a single 'master backend' and a bunch 
of 'remote frontends', unless you have multiple machines with tuner cards, in 
which case each machine with a tuner card can also be a backend.  When you 
have multiple backends, one of them must be designated the 'master backend'.


> 2. The documentation suggests that part of the slave backend does not
> need to be run but it isn't clear on if a TV input (re: a TV or PVR
> card) is required.  Can a slave run without a hardware TV input directly
> in the slave system?

A 'remote frontend' doesn't need a tuner card; a 'slave backend' (or any 
backend) needs at least one tuner card.


> 3. Can a slave with a TV card be configured to watch LiveTV directly
> from that card (without recording features)?  The reason this might be
> desirable is if the lag in a local network makes watching recorded
> LiveTV distracting then the user could switch to a more direct feed.

You mean a combination frontend/backend box.  Yes; you need to edit your XML 
menu files to launch xawtv (or your favorite TV viewer) using the EXECTV 
command.  This marks the tuner as 'in-use' and any recordings that were 
assigned to that tuner will be re-assigned or skipped, depending on ranking 
and availability of other tuners.


> 4. What does a master do (and what does the slave front end show) when
> no video input sources are available for either recording or live TV?

If no video input sources are available, then (1) for recording, the scheduled 
recording is not performed (2) for LiveTV, a message pops up indicated that 
all tuners are in use.

> 5. Can slaves access all of MythTVs add-ons via the master - for
> example, can games be fed to the slave to be run on the slave hardware
> and can photos (re: MythGallery) be viewed on the slave if they are
> stored on the server?  I know in the latter case you could set up NFS
> mounts, but I was wondering if there was a mechanism (either by design
> or already coded) that allows feeding the images via TCP to the slave
> for display?  This would be preferable to reduce admin overhead on the
> slaves.  

Currently NFS is the only way to go here, though integration with the backend 
has been discussed for some of the plugins.


> 6. Do recordings get streamed to the slaves or do the slaves have to
> pick them up via NFS mount points?  If the former, what protocol is
> being used for streaming?  RTSP?  Something simpler?

Served via the filesystem if available (locally or network-mounted), otherwise 
streamed using a custom TCP-based Myth protocol.

> I've got a couple of bugs to report.  Two are minor although I do need
> to track down a serious problem with stability when LiveTV is left
> running for extended periods.  This might be an ivtv problem, though the
> backend is segfaulting too.  Is there a Bugzilla location for MythTV?  I
> couldn't find a reference to one on the web site.  Also, if I make
> changes to the code, what is the proper way to submit them?  I don't
> know that I will make any changes yet, but I'm kinda expecting I will.

Both bug reports and patches should be submitted to the mythtv-dev mailing 
list.  Bug reports preferably with gdb backtraces; patches generated with 
'diff -u'.

> Thanks.

No problem.  Welcome aboard!

-JAC