[mythtv-users] Replicated MySQL database, dynamic 'master' backend....?

[Andrew Wilson]

Backend is small form factor Compaq ENS, PIII 550MHz, 256MB. Cost me
£20 delivered! I can't praise enough the design of this machine, it is
so modular and well thought out.

Frontend is a VIA M10k. It does not break a sweat using the hw mpeg
decoder, though I should have gone for a fanless model as then there
would be no moving parts other than a DVD drive, and would use less
power still.

NAS is a Maxtor shared storage. Runs linux and has been neatly hacked
(Openmss.org) so you can run your own programs on it. Has USB ports so
I have connected my printer, and a VCD screen (plumbed through to the
frontend so the frontend does not need to be on to display a clock).

I think I could do mysql replication, but there's not much point
unless I can get mythbackend to behave as I want.


On 21/07/06, David Rees <drees76 at gmail.com> wrote:
> On 7/21/06, Andrew Wilson <migmog at gmail.com> wrote:
> > BoxB: Diskless backend with capture cards in a cupboard
> > BoxF: Diskless frontend connected to TV and Hifi in the living room
> > BoxN: Low power embedded NAS with big disk, boot server, NFS storage, up 24/7
> >
> > Goals:
> > - Reduce power consumption: Currently using ~77W when watching
> > recordings, ~47W when recording, ~14W when idle. If BoxB was off when
> > watching, I'd save ~32W.
> > - Make boxes independent so BoxF does not have to wake up BoxB and
> > wait until it's ready.
>
> Wow, that is some great power consumption. My combination
> backend/frontend uses 100w idle and 15-20w more when active. :( It's a
> Duron 800, 2 PVR250s (10w each idle!), GeForce FX 5200 and a single
> 250gb 7200 drive. I estimate that replacing the Duron with a Sempron
> 3000 will reduce idle power by 10-15w, but I'd really like to get
> power utilization under 50w when idle. 14w would be awesome, can you
> elaborate on the setup of each of your boxes?
>
> > Is it possible to have 'mirrored' MySQL databases and backend process
> > running on BoxF?  I figure the BoxF backend would have to be the
> > 'master' while BoxB is down, and vice versa. There's no problem about
> > the boxes seeing each others files, because there's really only 1 fs
> > shared between the whole network.
>
> While you can use MySQL replication to mirror a database in a
> master-slave setup, I don't think there's anyway to run a frontend
> without a connection to the backend, or any way to "mirror" the
> backend process. I also think the frontend needs to write the
> database, so using MySQL replication won't work if the frontend is
> connected to the slave db.
>
> -Dave
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