[TriLUG] FreeNX versus VNC

[Aaron S. Joyner]

Tim Jowers wrote:

> Hi Everyone,
>
>  My teacher friend wants to share his disktop with the students -
> about 15. They are running FC5. Well, he tried VNC but after 6 users
> performance went to nil. I searched and found a package called FreeNX.
> Has anyone used FreeNX?  Or know how to optimize remote X displays so
> 15 students can see and possibly intereact with the display?
>
> Thanks for ideas and feedback!
> TimJowers

Did you do any poking around at the machine to see why performance went 
to 'nil'?  I could see two likely causes, either you were network bound, 
because 6+ VNC sessions to the same machine could cause a reasonable sum 
of traffic, or more likely you were CPU bound.  Depending on how you 
were running VNC, it's possible this was because you weren't using a 
native VNC X server, but instead were scraping the X11 display, which 
leads to much more VNC traffic - changing to a native VNC X server might 
help this.  Or, it could be the sheer computation and compression 
overhead was too much for the machine (which would be evident in equal 
cpu time being consumed by most of the VNC processes).  Too many 
variables (what type of processor / machine specs, what network 
hardware, etc) contribute to me being able to make an educated guess 
about the likely source of the problem.

In short, it's hard to say why this happened, and you'll probably want 
to collect some more data before you make assumptions about the right 
way to fix the problem.  You could just dive in and try NoMachine / 
FreeNX, it might "just work", but it's worth understanding the 'why' 
around i fit does or does not, imho.  :)

Aaron S. Joyner