[Udpcast] Cloning Live Machine

[Donald Teed]

On Thu, 22 Jul 2004, Felix Rauch wrote:

> On Wed, 21 Jul 2004, Lee Kransen wrote:
> [...]
> > If I understand correctly, it seems that the best option is for me to take
> > out the hard drive, put it in the DHCP/TFTP server and run the udp-sender
> > from there. Is that correct?
> 
> You could also setup an environment that boots into a RAM disk, with
> the help of DHCP, TFTP and PXE. We did that for our own 128-node
> cluster. The RAM disk contains the most essential tools and is
> otherwise kept at the minimum. In our case, the RAM disk uses roughly
> 80 MByte of our nodes' memory. When all the nodes booted into the
> RAM-disk-based system, we clone their disks (not with UDPcast, but the
> principle is the same).
> 
> - Felix

We're using PXE boot for udpcast.  What some people don't
realize is that the boot option support comes from the
network card's boot ROM, not the mainboard BIOS (although
it probably helps to have something semi-recent for the mainboard).
Most inexpensive retail network cards do not support PXE boot.
This is one of the distinguishing differences between
the equipment supplied in a "business PC/notebook" and
a similar model for "home users" - the ones marketed
as business models have network boot support in case
they need to be operated as client workstations.

Booting from a CDROM is normally something that is cheap to
add to a system with a $20 CDROM drive (cheap, relative
to someone's time in moving the hard drive back
and forth each time the image is freshened).  The only 
situation I can imagine where that isn't possible is
with an older laptop or a very old 486 and previous
generation machine.