[mythtv-users] Questions about master/slave BE

Nick Morrott knowledgejunkie at gmail.com
Wed Jun 9 08:51:45 UTC 2010


On 8 June 2010 12:22, Peter Carlsson <maillist.peter at home.se> wrote:
> Hello!
>
> I currently have a dedicated BE/FE that I power on/off according to
> scheduled recordings. I also have a general server for file sharing,
> web applications, backup and such that is already on 24/7.
>
> I would like this general server to also become the master MythTV BE
> and turn my current BE/FE into a slave BE and FE.
>
> This way the mythweb will be available 24/7 and it would also be
> possible to schedule new recordings whenever I want.
>
> Are there any pros/cons with this setup?

Other than ensuring the general server you are proposing to use as
your master backend has enough "spare capacity" (CPU/memory/HDD) to
function in its new role, not really. You should make good saving on
power as your fileserver is already on 24/7.

If there is a chance you might want to add more capture cards in the
future into the master backend, you might want to think about that. Of
course, if you are also running a slave backend/frontend, you could
add the additional cards into that - it really depends on how many
recordings you make.

If I was running a backend 24/7 (which I do at the moment) I would try
to put as many capture devices in the machine as I reasonably could in
order to avoid having to periodically run a slave backend. I don't use
commflagging/transcoding on the backend machine and only record SDTV,
so my CPU/IO requirements are still quite low when compared to
HDTV-based backends. I used to run a slave backend on a remote
frontend, but consolidated the capture cards into the master backend
when I rebuilt it back in 2006, and now frontends are pure frontends.
Things may change again once DVB-T2 is available here in the UK, but
things are working well now.

> I have installed the same version of MythTV BE on both machines.
>
> Would I have to do something else than:
> 1. Export database from current BE/FE
> 2. Import database on new master BE
> 3. Set new master BE to listen on its 192.168.1.x port
> 4. Point the current BE/FE to the new master BE 192.168.1.x port

See http://www.mythtv.org/wiki/Database_Backup_and_Restore#Change_the_hostname_of_a_MythTV_frontend_or_backend

You will need to delete and reconfigure your capture cards in the new
machine, as these are stored against the hostname of the machine they
are in. Frontend settings are also stored against a hostname or unique
identifier, so these will be lost unless you update the hostname they
are associated with.

> After this migration, will the slave BE sync to the new master BE on
> every power on and then periodically?

Not quite sure what you are asking. A slave backend does not run a
local MythTV database, or sync recording files with the master backend
- it acquires all settings from the database running (typically) on
the master backend. You could store recordings made on the slave BE on
the master backend/fileserver by exporting shares - this way
recordings made on the slave backend will still be watchable when it
is turned off - it really depends on the volume of recordings your
slave machine will make and whether the storage subsystem on the
fileserver will handle this additional load.

Cheers,
Nick

-- 
Nick Morrott

MythTV Official wiki: http://mythtv.org/wiki/
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