[mythtv-users] Some master/slave backend advise required

[Johan Van der Kolk]

Hi,

I’m running myth 0.27 (v0.27.1-7-g41d04b6) on Ubuntu server 14.04 with an i5(3GHz) and 4GB memory. I’m using 4 DVB-S2 tuners as source.
Due to relocation of the dish I have to install a slave backend. I can’t (don’t want to) move my server to the garden shed.

I have found that recording about 8-10 HD channels simultaneously will start killing processes on the backend (not the myth processes though), but the CPU load of the DVB-s2 stuff by itself requires 100% cpu. Mythcommflagging did not help either, although I could limit the simultaneous jobs to get more breathing space. 
So my thought was to solve both problems at the same time with a new slave backend, where the dvb-s2 stuff is running, by itself. Storage and commflagging still to be done on the master backend (which has 8TB of ZFS storage)

I can see two issues now:
Bandwidth: When recording 10 channels (what I want to achieve), I estimate worst case (based on what i recorded so far) 3GB per channel per hour, or 833Mb/s one way traffic, without other overhead. And not watching anything...
How to solve this, and does myth traffic between master and slave benefit from Jumbo Frames. I could use two network cards in each machine, and create a 2 x1 Gb trunk between the switches.
Second part of the problem might be that the ZFS file storage is not fast enough. (upgrade to SSD maybe)

Configuration:
Is it possible to configure mythtv in such a way that it does what I want, or are there better ways to do this? 

Any help appreciated!

Johan