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

[David Rees]

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