<div class="gmail_quote">Good afternoon Greg,<br><br>Thank-you for your reply, I just have a few questions.<br><br>- If I'm running Nova-Ts, why would I not be running commercial skipping? I am running it on all my recordings, and it <i>appears </i>to work (I don't actually use a MythTV frontend, so I have never actually tried skipping the adverts), is there something I don't know about the Nova Ts?<br>
<br>- Assuming I turn commercial detection off, would you agree that anything over 800MHz (the slowest Atom) would be fine for recording & file sharing?<br><br>- Do you know if USB tuners draw less power than PCI ones?<br>
<br>- Does recording more than one channel at once make much of a difference? At the moment I have the two tuners (on a single PCI card) set to record up to 3 channels each at the same time (to cover the over lap at the start/end of two recordings on the same channel). Theoretically (although it's never happened in practice) at the moment my set up could record six TV channels at once.<br>
<br>Many thanks for your very detailed help with this! It's just what I was looking for.<br><br><br><div class="gmail_quote">2009/10/20 <span dir="ltr"><<a href="mailto:mythtv-users-request@mythtv.org" target="_blank">mythtv-users-request@mythtv.org</a>></span><br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">---------- Forwarded message ----------<br>From: Greg Cope <<a href="mailto:gregcope@gmail.com" target="_blank">gregcope@gmail.com</a>><br>
To: Discussion about mythtv <<a href="mailto:mythtv-users@mythtv.org" target="_blank">mythtv-users@mythtv.org</a>><br>Date: Tue, 20 Oct 2009 12:44:24 +0100<br>Subject: Re: [mythtv-users] Power efficient backend-only server<br>
Hi,<br>
<br>
If you are running DVB Nova-T's I assume you are not doing Commerical<br>
skipping or transcoding.<br>
<br>
IF the above is correct, you need sod all processing power, just<br>
enough to cope with the IO (network or otherwise).<br>
<br>
Any atom based board/system would work fine (20w ish) (think nettop).<br>
Or a via based board (I use an SP13000 as a front/backend).<br>
<br>
To get a little over the top you will notice that the thermal (and<br>
hence power requirements) of systems these days are as much driven by<br>
their system board chip sets as the CPU - ie early atom boards had a<br>
low power cpu (5w?) combined with a heater, sorry, chip set that<br>
struggled to draw less than 15W.<br>
<br>
You can aim to get the board+disk to consume around 30W (20W for the<br>
system+cpu, 5w for each of disk+Nova-T YMMY).<br>
<br>
Thus do NAS'es - I believe (But could be wrong) that all the small<br>
NAS'es run linux or freebsd underneath. Although you will find it<br>
hard to find, you need to be carefully about the power draw of a<br>
NAS/always on thingy - see below for my USB/ESATA enclosure power<br>
draw.<br>
<br>
To give you a benchmark my FEBE draws 60W and includes;<br>
<br>
SP13000 board+CPU<br>
2xNova-T PCI cards<br>
2x400 SATA drives<br>
1x750 GB PATA drive<br>
<br>
Sadly the age of the chip set/OS release means it cannot do drive spin<br>
down as that would save another 15w average.<br>
<br>
I am planning a replacement with a Acer Revo (20w-30W), USB twin Tuner<br>
dongle (5w?), and a 1.5TB ESATA drive (5-7w). This should drop to<br>
around 40W, less at idle. Presently strugging to get my ESATA<br>
enclosure to draw less than 7w when the drive inside (1.5TB Samy green<br>
power) should only be drawing 4W (ie the transformer/chipset<br>
efficiency is rubbish at nearly 50%).<br>
<br>
Why am I so anal about this? Simple - dropping 20W of continuous draw<br>
saves around £20 a year (at present prices), or £80 over a 4 year<br>
life. Also lower power means low heat, low noise, and hopefully<br>
better reliability (due to less heat issues).<br>
<br>
Greg<br>
<br>
2009/10/20 Vitani <<a href="mailto:vitani-mythtv@tfxsoft.com" target="_blank">vitani-mythtv@tfxsoft.com</a>>:<br>
> Good morning all,<br>
><br>
> I currently have an old desktop PC running Mythbuntu (backend-only), using a<br>
> Nova-T 500, but it's big, loud, and relatively expensive to run. I was<br>
> thinking about getting a mini-itx motherboard (or smaller!), which used a<br>
> laptop hard drive, all in a nice small case, and pair that with a<br>
> Linux-based* commercial NAS (so should the MythBox die I can still access my<br>
> other media). That's the plan, but I'm not sure how much processing power a<br>
> backend-only system would need. There seems to be a lot of articles on the<br>
> Wiki about hardware, but most are out of date (they talk about version 20),<br>
> and/or focus on front-ends or both-end set-ups.<br>
><br>
> I had a look on the PVR Hardware Database and only one entry really seemed<br>
> to fit what I was looking for -<br>
> <a href="http://pvrhw.goldfish.org/tiki-view_pvrent.php?systemid=Myth%20BackEnd%20Only" target="_blank">http://pvrhw.goldfish.org/tiki-view_pvrent.php?systemid=Myth%20BackEnd%20Only</a><br>
> - but that set-up used a 2GHz Pentium 4, which I obviously would not be able<br>
> to run on my planned system.<br>
><br>
> So my question is, has anyone created a backend-only MythTV system using a<br>
> small, power efficient computer, and if so, what components did you use, and<br>
> how well does it run?<br>
><br>
> PS. If anyone knows of any commercial NASs which do run Linux, could you let<br>
> me know, as I've not found one yet.<br>
><br>
> * the NAS doesn't have to run Linux, but I'd like to be able to set up<br>
> symbolic links from the NAS to the MythBox in order to access the recordings<br>
> directly over Samba.<br>
><br>
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