Remote Mains Power Control of Backend by Frontend(s)

[wildpossum]

Hi All.

I have five frontends (Zotac ION M/boards) running HDTV just amazingly with MythTV from a quad core AMD server with five concurrent dvb streams.

I wish to automate the mains power to the MythTV backend server to conserve energy.

I am thinking of using a low-cost Linux based embedded controller (as there cheap as chips - or if need be, design and make freely available just such a device for the DIY brigade) to control the MythTV Backend mains power in a effort to reduce the power-footprint of the system(s) as much as possible. It will be better for our environment too, and will keep those power bills to a minimum.

Naturally, Backend power-on state would be whenever there where schedule recording(s) to take place, OR if MythTV was already recording AND/OR if any frontend powered up and require MythTV service.

Looking at the mythtv initial-setup, it seems that some sort of powering provision is available to allow the backend to sleep, more so than to power off. To what extent is the current builds looking at functionaly controlling the backend power - other than simply allowing the backend to go into sleep mode?

Concept wise just a simple ethernet connection listening on tcp ports for service request from frontend(s), together with a in-memory cache of scheduled recording times using either a mysql-client lookup or maybe some simple tcp data updates, ntpd incorporating simple web based controls. Power control would use simple and freely available solid state modules with fully opto-iosolated inputs via USB or DIO.

Are there any development intensions already planned for just such functionality?

Comments greatly appreciated.

Cheers. Grahame

[thrytis]

Are you just trying to shutdown the backend when not recording and the frontends are off? If so, you can just use the bios wakeup to have the backend turn itself on to record and the wake-on-LAN to turn on the backend when a frontend is turned on. Both features are pretty standard on current hardware, so you probably don't need to buy anything new to get it to work.

[wildpossum]

No, I am also wishing to allow other conditions of power on/off to be used relative to:

1> Next scheduled recording time,
2> Any front-end(s) starting up and waiting for backend service,
3> Intranet request from other clients wishing to access the MythTV Backend for other work - eg: Maybe having the Backend(s) also serving as the master LDAP, NIS, Backup machine, or AoE server.

Your idea though has good merit, because it maybe possible to use NVRAM kernel module and MySQL client to configure and regularly set the BIOS wake-up nvram parameters of the backend device(s).

Cheers. Grahame

[thrytis]

For item 1, the bios wakeup will do the job. Once you set the mythtv backend configuration, mythtv will run a script to check if it is okay to shutdown, and if so, it'll set the time to wake up and then shutdown the computer. You have control over the shutdown script, so you can check to see if any other clients are connected for other services, e.g. someone is logged in or a local file system is mounted by another computer.

For item 2, just call "wakeonlan <backend>" in a startup script on the clients. This will get the backend booting while the front end boots.

For item 3, have your clients call wakeonlan to start up the backend when they need it. I'm sure there are equivalent utilities for Windows and Macs.