[mythtv-users] backend 4x pvr250 MB advice
bob at smalltime.com
Fri Jul 30 13:22:49 EDT 2004
> Couple of points to the OP:
> You either will need gigabit ethernet, or several 100mbit cards in the backend
> to serve frontends I think. It's rather dubious if 7 frontends can be driven
> though just one network card. The issue of disk I/O and PCI bandwidth plays,
> too. You need to experiment, I would not expect a system to be able to
> maintain 4 recording streams and 7 frontend streams at one time, albeit that
> worst-case scenario will not happen often at all...
I've regularly seen linux boxes pushing in excess of 88mbps on a 100mbps
link, so 7 frontends shouldn't be an issue unless the bit rate is
cranked up very high. The MythtV default 3mbps/6mbps MPEG2 looks good,
so there's plenty of overhead on the ethernet side if you're using the
default bit rate on the encoders.
> Maybe splitting the backend into two separate boxes with Gig-E between them
> and two cards in both will work better, I dunno. That would at least help
> with the network bandwidth, as not all frontend streams will be served by the
> same backend. This setup of yours is kind of uncharted territory of course,
> and that is obviously why you're asking here.
I'm not saying that you _shouldn't_ use GigE, if the cost is low enough
(the cost per port on the switch side is higher than 10/100, but that
will be coming down soon enough.). Just not sure that it would be
required off the bat. If you're really looking for future expansion,
then you could always start with a GigE on the motherboard to a 1xGigE,
16x10/100 switch. That way you're minimizing the costs since those
frontends don't need anything like GigE.
Also, Toms Hardware seemed to like the built-in Intel GigE
More information about the mythtv-users