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

Hika van den Hoven hikavdh at gmail.com
Mon Jun 2 19:14:23 UTC 2014


Hoi Johan,

Monday, June 2, 2014, 8:59:49 PM, 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

I would always keep recording and storage on the same machine. You
could move the database, commflagging, metadatalookup etc to a slave.
Alternatively you could split up your recorders and the storage space
over both machines.


Tot mails,
  Hika                            mailto:hikavdh at gmail.com

"Zonder hoop kun je niet leven
Zonder leven is er geen hoop
Het eeuwige dilemma
Zeker als je hoop moet vernietigen om te kunnen overleven!"

De lerende Mens



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