[mythtv-users] Proposed future power saving networked configuration (0.22 in mind)

Ben Coleman arrikhan_mail at yahoo.com.au
Sat Feb 21 00:12:48 UTC 2009


Chris Pinkham wrote:
> You're assuming that people can fit all their tuners into a single
> master backend.  You haven't been using Myth long have you? :)  

I haven't changed much since installing it... but have been using it 2+ 
years with mostly 5 year old kit except tuners, but I installed 2 x dual 
HD tuners consuming only 2 slots. 4 tuners total is plenty (for me). I 
learnt a lot from all the people who've been there before me to 
consolidate at the start, otherwise I'd end up with too much kit and the 
possible need for another box. Your "spin" on this problem seems a 
sensible approach to management of this as well as recycling the copious 
amounts of older kit laying around!  :)

> I
> personally have  5 PCI-based tuners right now counting the 3 M179 analog
> and 2 air2pc ATSC cards.  Putting them all in the master would be one
> feat because I'd have to find a motherboard with at least 5 PCI slots,
> and that would either have to be new enough to have Gig-E onboard or
> have 6 slots so I could install a Gig-E nic.  These numbers are
> partially out of the blue, but if my WOL slave uses 35 watts by itself
> and 55 with the 2 air2pc cards in it, then it would consume about 500
> watts for those 9 hours of recording over a week.  If the same 2 tuner
> cards use 20 watts 24x7, that would be 480 watts per day for a total of
> 2660 per week.  This is assuming 10 watts per card.  Even if you half
> that, you'd still be at 1330 per week vs about 400 for the WOL slave.
>
> These numbers aren't as good if you use a power-hungry P4 @ multi-Ghz
> that consumes 100+ watts by itself as your WOL slave.  If you don't need
> a lot of horsepower and can use a lower-powered older computer or a
> newer atom-based motherboard somehow, then the numbers are much better.
>   

I can see the benefits here, because in reality, you spend a small 
proportion of your time capturing video. The Master has to always be 
there for more than just capture as I'd watch more than I'd capture 
through video file watching and the like. Dropping a Master in VM would 
be fantastic as you can keep snaps/clones etc and effectively never have 
to rebuild from scratch. I'm dreading my rebuild of my backend since I'm 
changing hardware. I've dropped my old HD's onto the new kit and it 
'works' but linux isn't going to take advantage of the new CPU cores 
etc.. and my Linux skills aren't at the level to make magic happen here 
so I'll start again and relocate the recordings I have.

> If you wanted to take advantage of wakeup on demand slaves, then you'd have
> to see if there was a benefit.  In my case, it means I could turn off
> all systems with tuners physically in them (ie, not that HDHR slave on the
> fileserver) for at least 1/2 to 2/3 of the day, and with multirec on the
> HDHR, some would be off for most of the week (in my case 159 hours Off
> compared to only 9 hours On for the whole week).
>   
> Sure, it will take me years to save enough power to pay for my
> programming time to add this feature, but if it's $5-10 less that I'm
> paying the power company each month it's worth it now.
>   
Yeah, I'm tired of seeing the "It's only 5 watts extra a day ... the 
world will live with it, and it only costs me an extra $10 a year", but 
in reality, if everyone was more conscious about the power they waste 
(like you are!) we might be in a better situation than we're in today 
environmentally.. If Myth can support the flexibility here, we need to 
abuse it :) The blackbox dvd-player, stereo etc.. etc.. manufacturers 
are certainly not rushing to reduce power consumption they inflict 
around the world.

> One note. I've used WOL in various places in this email, but the
> WakeUpCommand is an actual command in my patch, it can be anything to
> turn on a system, the same as the current WOLslaveBackendsCommand
> setting except mine is for each server specifically instead of a global
> command to wakeup all slaves.  I do support the special case of the
> WakeUpCommand being just a MAC address.  If this is true, the master
> will use builtin code to send a WOL packet so the user doesn't have to
> install any more apps to use WOL.  In my case I'll use WOL probably, but
> I could just as easily send commands to my Baytech power strip to power
> On/Off receptacles to turn slaves On/Off.
>
> --
> Chris
>   

Thanks very much for your summary... Understanding the thinking of how 
you got to your current configuration makes me see the benefits more 
clearly. With the three old P3's in  my garage gathering dust, I am 
seriously considering bringing them back to life for this purpose. The 
new Quad core box can be stepped down to consume less power overall and 
serve the multifunction server it does today including a tuner-less 
backend. Secondly, a new renovation I'm about to go through is moving my 
'server farm' into the house so I'm looking for EVERY opportunity to 
reduce power, noise and heat since this stuff will sit in a cupboard in 
the hallway.

I might spring this question in another location but thinking aloud, 
multiple HD tuners recording simultaneously to an NFS mount? .. can it 
work over 1 x Gbit?


Regards,


BC.


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