[mythtv-users] Freevo, Tivo & MythTV

[Paul Bender]

Marco Nelissen wrote:
>> Marco Nelissen wrote:
>>> You're lucky then. I have to wait anywhere from 6 to 17 seconds to go to
>>> live TV, and channel changing is about 6 seconds on a good day.
>> I see the long delay when I start live TV mode, but from then on channel
>> changes are only a few seconds.  Certainly not six.  I suspect the long
>> delay on switching to live TV is because I don't have enough RAM and the
>> system is swapping when I change from one function to another, but I
>> haven't bought another stick of RAM to verify this, yet.  With only 256
>> megabytes of RAM and both the frontend and backend running I use a
>> significant amount of swap.
> 
> I have 512MB and it's a combined front/back end. I read that mythtv
> requires 256MB, so I figured I'd double that and be extra-safe. Would
> adding more memory help in any way with channel-change speed?

You might want to consider more memory.

I maintain a diskless MythTV frontend distribution <http://linpvr.org>. 
Since it runs on systems that have no disk, the systems have no swap. 
While 256MB was sufficient for earlier versions of MythTV, I have found 
that you really need more than 256MB (e.g. 512MB) for MythTV 0.19 and 
MythTV 0.20 just to run a MythTV frontend only system. Maybe the fact 
that nothing on my MythTV frontends ever swaps contributes to the better 
performance that I am getting.

A combined system adds things such as tuner card drivers with their 
required buffers, a mysql server, mythbackend, commercial flagging 
processes, etc. I would imagine that requires a non-zero amount of 
memory. However, I do not know how much. My home server that runs my 
MythTV backend has 2GB of memory, which provides a very loose upper 
bound. However, I am sure that the actual requirement is much less.