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

[Johan van der Kolk]

On Tue, Jun 3, 2014 at 2:27 PM, Stephen Worthington <
stephen_agent at jsw.gen.nz> wrote:

> On Mon, 2 Jun 2014 20:59:49 +0200, you wrote:
>
> >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
>
> Have you had a look at vtuner (virtual tuners)?  If it works with the
> drivers for your DVB-S2 cards, that would allow you to have a minimal
> Linux box in your shed with just the real tuners and ethernet in it,
> and have the tuners appear as though they were on you main backend
> box.
>
> https://code.google.com/p/vtuner/
>
> There are also commercial boxes with builtin tuners that use vtuner.
>

Thanks for the tip, but I believe I achieve the same with a slave backend
and use the master backend storage pool through nfs. I'm just fooling
myth..But maybe I see this wrong. Nevertheless its unlikely that my drivers
will support this, as they were compiled from the TBS development tree.

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