[mythtv-users] Optimal disk configuration for MythTV?

[John]

On 30/12/12 11:11, Jelte Veldstra wrote:
>>
>> Cool detailing, thank you. Great food for thought. May I ask which version
>> are you running of myth now?  Is this power consumption calculated or
>> measured, if measured by what means?
>>
> An Intel system with a Sandy Bridge or Ivy Bridge CPU and a H61/67/77
> Q61/67/77 would draw about 20W idle without harddisks, OS on an SSD
> and a Pico PSU or any other efficient PSU. With some tweaking you may
> even get a little close to 17W. When adding harddisks a rule of thumb
> would be that green 3.5" drives draw 4-6W idle and "normal" 3.5"
> drives 8-9W idle. Laptop drives are interesting for low power builds
> as well and may take little more than half of the 3.5" drives. These
> numbers are based on personal experience where I measured consumption
> using a wattmeter (Voltcraft Energy Logger 4000) and experience shared
> in fora on this topic.
>
> So getting a system that stays well under the 100W mark is very
> feasible. Under 50W should be relatively easy as well as long as you
> limit the number of harddrives. The version of MythTV should be
> irrelevant when it comes to power consumption. For Intel based builds
> http://lesswatts.org is an interesting site offering power saving
> tips. AMD based builds can be very efficient as well, so it is
> definately not a must to go for Intel if you want something power
> efficient, but in fora there is less information on AMD builds
> compared to Intel.
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>
Got to agree with this.

I've been running mythtv for 10 years or so, and have been through 
countless sets of Hardware. I've jumped back and forward trying power 
hungry old hardware with screaming fans, to newer hardware that went to 
sleep overnight to NAS based backends. NAS/ARM based stuff is just too 
slow, and always requires lots of fiddling to get to work. The mini ATom 
based boards are more mainstream, but are slow and always seem to use 
more power than you expect.

I've pretty much settled now on running low end Intel systems, always on 
and doing as much as possible on the one box. So I have an "always on" 
desktop machine, home server and mythbackend in one box.

So you burn power all the time, but it is mainstream, cheap and if you 
work out how many times you turn on the PC to check email etc, you are 
not wasting that much.


OS (Ubuntu 12.04 LTS) mysql etc are all running on a 64G SSD, so no 
spin-up when not recording/playing back. This makes a real difference 
to  speed, particularly database access, power
and noise.

I have 2x 1.5 TB samsung green drives, 1 WDx2 TB, 1 Seagate x 2TB, all 
for storage. I have an external 3TB WD drive as backup (rsnapshot) which 
I mount and dismount by cron to make sure it stays asleep. I do let my 
storage drives spindown when not used.

CPU is a e530 Dual core sandybridge on an h61 motherboard. I have 1 USB 
DVB-T, and a dual DVB-S2 cards as tuners.

Most of the time the system idles at about 60Watts at the wall, ( using 
a killawatt/Maplin power meter) and when needed there is enough grunt to 
do other stuff (trans-coding compiling etc). With a modern processor, 
you can even underclock to save power.

Having "tried it all" I found you can spend serious money to try to 
bring down the power to a minimum, but the base power usage of the 
tuners and HDs is what will drive it all back up from that theoretical 
minimum. So my recommendation is use modern cheap bottom of the range 
components.The power at idle is a bit more than the absolute minimum you 
can get away with. ( my revo frontend is about 20Watts, the setup with a 
full size sandybridge processor is about 35-40 Watts for the equivalent 
base components ) Even in the UK thats still only another £20 of 
electricity a year always on.