Low power/low noise server

[DylanHall]

I've recently finished building a low power/low noise server for SageTV and thought I'd document the experience.

Motivation:

* Recently played with an Intel Atom board and it impressed me, I wanted to play some more
* Existing sage server is doing a whole bunch of tasks (virtual machines, file server, desktop, web server, sage server). Want to isolate sage from those other tasks and get it running on a dedicated hardware to avoid resource contention.
* Existing server is running 32bit Ubuntu to support sage. I would rather run 64bit. Dedicated sage server can run 32bit without imposing that limitation on anything else.
* Reduce power consumption
* Move sage server into lounge which will make it considerably closer to the the aerial (shaves around 25m off the length of the coax run). The server must be low noise if it's going to live in the lounge.

What I've built:

* Intel Atom M/B, D510MO, Dual Core Atom 1.66Ghz.
* 1GB RAM
* Hauppauge WinTV Nova T 500 (pci dual DVB-T tuner)
* DC-DC power supply (http://www.mini-box.com/picoPSU-80-60W-power-kit)
* 1TB Western Digital "Green" HDD (OS + Recordings)
* 1TB Seagate 7200.12 HDD (other media: e.g. jpg, mp3, avi, mkv)

The server is required to feed 2 x HD200 extenders.

I chose the Intel board because it's passively cooled.
The DC-DC power supply is pretty limited (60 watts) but is also completely silent.
The only source of noise in the machine is the hard drives. These are hard to hear unless you listen for it. If there is any other source of noise in the room (watching tv, heat pump, dish washer running in the kitchen, etc) I can't hear the machine at all.

The total power consumption is around 30 watts when idling with peaks in the 35-40 watt range under load.

I've been using the new server as my primary sage server for a couple days now without any issues

The only time I've managed to cause an issue was getting my bit torrent client to write directly to an NFS share on the new server. The client thrashes the disk (seeks all over the place) which caused live tv viewing to stutter (load average on the server was ~8). There is something deeply wrong with the way rtorrent interacts with NFS

Watching a single 1080i live tv program on the HD200 causes the sage process to consume 10-20% CPU.

I tried the 7.0 beta software briefly which ran well. Only issue was creating thumbnails for ~7000 jpg files which took ages and consumed 100% of one core. The thumbnail generation was clearly being limited by the low performance of the Atom CPU.


Caveats/Limitations:

* Only a single PCI slot on the Atom M/B.
* Limited to 4GB RAM (single channel memory controller so memory doesn't need to be installed in pairs).
* Only 2 SATA ports, no PATA.
* I wouldn't want to guess how the server would perform running windows rather than linux, but my cynical anti-microsoft background suggests it will struggle. I certainly wouldn't try it without first adding some more RAM.
* I doubt the Atom would have the grunt for some of the more complex builds I read about in the forums (6 tuners, 4 fronts ends, etc).
* I've never used the "video conversions" feature, but I suspect it would struggle with the Atom CPU.
* Don't do this to save money! There are lots of ways to calculate his, but I estimate it will take 5-7 years of power savings to cover the cost of the new hardware.
* Silent PC's are creepy There is something unnatural about switching on a PC and not being able to hear it.

[david1234]

Originally Posted by DylanHall

Caveats/Limitations:
* I wouldn't want to guess how the server would perform running windows rather than linux, but my cynical anti-microsoft background suggests it will struggle. I certainly wouldn't try it without first adding some more RAM.
* I doubt the Atom would have the grunt for some of the more complex builds I read about in the forums (6 tuners, 4 fronts ends, etc).
* I've never used the "video conversions" feature, but I suspect it would struggle with the Atom CPU.

I think the atoms are a lot better than most people think. My wife's netbook running winXP with the single core atom, runs circles around my p4 at the same 1.6ghz, and it has handled everything I can throw at it just as fast as my core-duo at the same 1.6ghz.

[bcjenkins]

Commercial detection?

[brewston]

Which case did you use ? I've got a low noise server, with a less powerful CPU than the Atom even. As you say, when watching via HD200 it doesn't work very hard at all. You may be able to install a dual PCi riser to add another card, depends on the case. I've only got 1 PCI card in mine though, the DVB-S2 one as the DVB-T tuner is USB

[Fuzzy]

Commercial detection shouldn't be much of a problem for the dual-core atom. The bigger limitation would be that he's running on Linux, so options are limited in this regard. It only has to be able to keep-up with the analysis as it records, which shouldn't be a problem (can probably do at least 2 shows at a time on that hyperthreaded atom dual core).

[bcjenkins]

Comskip works fine in Linux. I am more concerned about h264 scanning.

B

[roymcd]

I've got a similar setup to DylanHall now but I have server performance problems as per below.

Hardware -
Intel Atom M/B (ASUS MB), D510MO, Dual Core Atom 1.66Ghz.
2GB RAM
DViCO FusionHDTV DVB-T Dual Digital 4 (rev 2)
Aywun MD-100 case with external power pack
1TB Western Digital HDD (OS + Media)

Software -
Ubuntu 10.10 32-bit server (maverick Meerkat)
java version "1.6.0_20"
OpenJDK Runtime Environment (IcedTea6 1.9.7) (6b20-1.9.7-0ubuntu1)
OpenJDK Server VM (build 19.0-b09, mixed mode)
SageTV V7.0.23.1

HD-200 STV version is 2010110101

The server is required to feed 2 x HD-200 extenders and I also use a Windows Placeshifter client for testing and occasionally to watch TV. It also acts as a fileserver to the PCs at home.

I was previously running a DELL Optiplex GX270 (2.6GHZ? P4 with 384MB) and Ubuntu Desktop. Performance-wise the Dell worked find as a SageTV 7 server and I expected the dual-core atom to cope just fine, especially since I switched to Ubuntu Server and dropped all the extraneous processes that Ubuntu Desktop runs. However, I've been very disappointed with how long it now takes for the HD-200s to get to the main SageTV screen from boot and how much (up to ~300%) CPU is consumed on the server when an HD-200 is booting. I also can't believe when moving around in the HD-200 menus how much CPU load is placed on the server side. Its not hard to get the CPU use to ~200%. I believe Ubuntu is reporting 100% for one core-thread using 'top' and that 400% represents all 4 core-threads being fully utilised.

Can anyone help me understand why CPU use on the server would go so high when all I'm doing is using the remote to move around the menus on an HD-200 and, more importantly, if there's anything I can do to keep the CPU load down. If someone is watching live TV on one of the HD-200s and someone else boots the other HD-200, the picture and sound on the first one starts breaking up when the server CPU use goes through the roof. Once both HD-200s are running and watching TV there's not much CPU load on the server, but if someone starts moving around in the menus the server CPU hikes up again and can cause breakup on the other client.

[DylanHall]

My setup is still humming along nicely. I've certainly not seen the high-load issues you're experiencing.

A couple thoughts:

I had some issues with the DVB USB driver polling a non-existent IR receiver which pushed the load up considerably. Adding the following to /etc/modprobe.d/local.conf fixed it.

# disable remote control polling for usb dvb sticks
options dvb-usb disable_rc_polling=1

The DVB issues exhibited as a load average of around 0.5 while the machine was doing nothing. It didn't show up in top because the DVB driver is buried somewhere in the kernel.


In terms of differences between my setup and yours, I'm using Ubuntu 10.04 server (e.g. no X/desktop installed).

Also, I'm using the sun version of java rather than the openjdk build, e.g.

apt-get install sun-java6-jre

I think you need to enable the partner repositories for that to work.

Dylan

[roymcd]

Thanks for the quick reply and suggestions. I've got some grumpy family members since I made the switch to this hardware:-) The fact that your very similar setup is working smoothly is encouraging. It suggests that this is fixable. My tuner card has inbuilt IR receiver which I'm not using so I tried including the disable_rc_polling=1 dvb-usb option. Unfortunately it didn't make a difference. I also downloaded the latest Sun JRE and setup Sage to use it. No change:-(
I've logged a support call with Sage for this to see if they have any ideas.

If you get a chance would you please let me know what CPU utilisation the java process sits at when its not doing anything and then when you first turn on one HD-200.

Also, what CPU load you get while you are moving around the menus in the UI.

I'm wondering whether there is a parameter somewhere I can change to reduce the load.http://forums.sagetv.com/forums/imag...onbanghead.gif

[RocKKer]

Are you sure Sage is using Sun Java? What Java does the HD200 say when you go to system info?

Another thing to check while you have the system info up is Java Heap. I set mine to 1GB, I have 3 HD200's, IIRC you can set Java Heap up to 2GB.

I don't have an atom but my U10.10 server idles at 1-2% - don't know if there is a spike at HD200 startup or not.

I wouldn't expect an HD200's to impact the CPU that much, because your server acts mostly as a file server (which is generally pretty light duty). Placeshifter will impact the CPU greatly, I wouldn't use it until you get the HD200 performance problem figured out then I might cautiously try it.