On 8/20/07, David McNab <[EMAIL PROTECTED]> wrote:
>
> Hi,
>
> I'm seriously thinking of getting a bunch of free/cheap old boxen to use
> as Cin render farm nodes. A few questions come to mind:


Planned obsolescence and Moores law  are your friends.

1) Compiling - is there a way of ./configure-ing and compiling a Cin
> renderfarm node, such that it doesn't need X or any graphical libs? I'm
> preferring to have the nodes headless. Or would I need to temporarily
> install X and other gui libs for compiling, then uninstall them?


Use ssh to get into the box and run
cinelerra -d 400
to specify background rendering without gui
Keep the shell prompt open and you will get Rendering info started finished
etc.
However you need to run cinelerra gui on each machine to set up preferances,
network adress etc as it uses ./bcast configuration settings .

2) For (say) 8 nodes, would a 100Mbit/s LAN be fast enough, or should I
> stick a second NIC into my workstation and run 4 nodes off each NIC?


  Yes I would stick a 2nd nic in by all means. GB cards are cheap now. Use
swithes as opposed to routers as they are faster
100mbs does bottleneck IMO

3) Has anyone done any metrics on renderfarm performance? For example,
> is there a linear relationship between render speed and aggregate
> processor power?


Well it's not really an agregate by definition if I'm understanding you
correctly, cinelerra divides up frames and parses them in chunks to each
machine. The slowest machine renders slowest. How it determines load
balancing I'm not sure.

4) What's the optimal ratio of memory to processor for a renderfarm
> node? What I'm thinking is that too much memory for the processor could
> be a waste, while not enough memory would have it RAM-bound.


More memory is good 1gb per node recomended.

5) Apart from the disk space needed for software/swap, how much minimum
> free disk space should be present on each node for temporary file
> storage?


More is better, I use a 1.2 TB raid0 array  1/2 hour hdv is about 4.5 gb
By default background rendering goes to /tmp/brender it needs to be as big
as the file is. Depending on the size of your primary partition /tmp space
can fill up pretty quickly.

6) Any other performance/reliability/tuning considerations, to get the
> best outcome?


Here's what worked for me and worked really well. 3 machines we call 1)
master  2 & 3 render nodes. Assigned static IP adresses w GB ethernet for
our example I used :

Master (1) 207.104.128.11
Slave   (2) 207.104.128.12
Save    (3) 207.104.128.13

Take the time and google how to set up paswordless SSH authentication's so
you don't have to stop and enter Password. Another reason for 2nd nic open
connections on your network. Use DHCP for the outside world.

I set up a seperate user for my rendrfarm to keep paths identical in respect
to each machine.  I called it /home/movie (renderfarm user is "movie" with
identical passwords on each machine. Each machine had a dedicated drive for
media and background rendering. (250 gb ea)
On master(1) drive was mounted as  /mnt/media1
On slave   (2) drive was mounted as  /mnt/media2
On slave   (3) drive was mounted as /mnt/media3

Edit fstab or mount the drives respectively via NFS
from the Master: (script)
#/bin/sh
mount 207.104.128.12:/mnt/media2 /mnt/media2 &&
mount 207.104.128.13:/mnt/mdeia3 /mnt/media3
ssh 207.104.128.12
mount 207.104.128.11/mnt/media1 /mnt/media1 &&
mount 207.104.128.13/mnt/media3 /mnt/media2
ssh 207.104.128.13
mount 207.104.128.11/mnt/media1 /mnt/media1 &&
mount 207.104.128.12/mnt/media2 /mnt/media2

So now from any of the nodes /home/movie/mnt/media1 is the same path whether
it's local or NFS This makes it really easy to keep track of things.
Particularly since each node needs to know where  resources are. Open
cinelerra and set up your project on the master node with format and
preferances.  Including renderfarm info located in >preferances>performance.
In preferances performance note background rendering. To get started click
it off.  Load some files. Do not add any effects yet. Save it as
/home/movie/mnt/media1/mybigmovie.xml

Open a console and run

ssh 207.104.128.12
cinelerra -d 400 /home/movie/mnt/media1/mybigmovie.xml
ssh 207.104.128.13
cinelerra -d 400 /home/movie/mnt/media1/mybigmovie.xml

On your timeline add some computationally challenging effects. Go to
>preferances>performances and Background Rendering click it on.
Your renderfarm should start to chew on your rendered effects as noted by a
red progress bar on the timeline. Resist the temptation to run cinelerra as
root because background renderings will get stuck in /tmp/ or whatever and
be undeleteable by user.

Kind Regrds
Daniel Jircik



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