[mythtv-users] PXE booting (was Spin up delay for HDDs)

Alex Tomlins alex at tomlins.org.uk
Mon Sep 26 19:11:03 UTC 2011

On 26/09/11 19:26, Ramon Hofer wrote:
> On Mon, 26 Sep 2011 18:55:24 +0100
> Alex Tomlins<alex at tomlins.org.uk>  wrote:
>> On 26/09/11 18:42, Ramon Hofer wrote:
>>> Btw: You boot your FEs with PXE. How long does it take to boot them?
>>> I'm thinking of PXEing my FEs too.
>> I'm PXE booting one of my frontends (roughly following
>> http://www.mythbuntu.org/wiki/network-boot-mythbuntu-diskless), and
>> it boots in around 30 seconds. Around half of that is the Bios stage
>> etc.
>> I'm running this on a gigabit network, and before I upgraded the
>> switch it was a fair bit slower, but still probably under a minute.
>> The only problem I have with it is that suspend doesn't work
>> properly. I think that's because the suspend process takes the
>> network down too soon, and then the root filesystem is unavailable to
>> continue the process.  Other than that it works well.
> Oh, that's interesting.
> Thanks for the link!
> I have a frontent that boots from an old SSD (Super Talent UltraDrive
> ME SSD 32GB) that takes about that amount of time as well.
> Just for my understanding: When you want to update the OS for the
> disk less system you build another PXE image with ltsp-build-client?
Not quite...

Basically it creates the full root filesystem under /opt/ltsp/i386 (or 
amd64).  It then generates the disk image from that directory.  Any time 
you want to update the image, you can just chroot into that directory, 
and do stuff (apt-get upgrade, install autobuilds, etc...), and then 
just run ltsp-update-image.

They go into this briefly towards the bottom of that article.

When the client is booted, it mounts that disk image read-only, and then 
overlays an nfs mount on top. Any writes get written to this nfs mount. 
They ends up in /var/cache/mythbuntu-diskless/<something>/ on the 
server. I think the <something> is the mac address by default, but I've 
tweaked my setup to use the hostname.  Look in 
/opt/ltsp/amd64/etc/initramfs-tools/conf.d/ltsp for those details.  I 
think you have to run ltsp-update-kernels after changing that.

The advantage of this overlay scheme is that you can run several 
frontends from the same image.

good luck.

Alex Tomlins
Email/Jabber: alex at tomlins.org.uk

There are two kinds of people in the world: those who finish what they started

More information about the mythtv-users mailing list