[mythtv-users] Shutdown unused slaves

[John Armstrong]

From: "Bob" <spam at homeurl.co.uk>
> Nick wrote:
>> This could be very useful if the MBE scheduler added new recordings
>> for the SBE machines to record as WOL could wake them up at the new
>> time, whereas a SDWU script using nvram-wakeup or similar would not as
>> the wakeup time is hard-coded in the BIOS. It's certainly a feature I
>> look forward to.
>
> I thought MythTV already used WOL to power up SBEs when needed for a
> recording, as for the rest, I have no idea how hard such features would
> be to implement, or if they're planed, do you?

Only seems to use WOL for the master to wake the slaves when it starts up.

I'm tinkering with a simple script to run on a slave to check if it is 
needed and shutdown if not. Will post it if it works OK. I don't use comm 
flagging at all (seems unreliable on UK recordings) and don't transcode 
much, but shouldn't be difficult to do a similar script to run on the master 
to wake up slaves if job queue is long.

I think my approach could cause scheduling problems in some cases that would 
need some real work at the scheduling system, eg with Master+Slave, each 
with 1 tuner:
program 1 8pm-10pm, normal priority, scheduled on master
program 2 9pm-10pm, high priority, scheduled on slave
at 5pm, slave decides it isn't doing anything for a few hours so shuts 
itself down until 8:55pm.
Master notices slave is no longer there, doesn't know it is going to wake up 
again, so cancels its 8-10 recording in favour of the higher priority 9-10 
recording.
Slave wakes up, but has nothing to do. 8-10 recording gets missed.

It may be possible that use of source priorities may avoid this, but 
otherwise, the scheduling system would need to know when currently offline 
backends will be online.

John