CentOS - Sep 2011 - xvfb question

First, I realize this might not be the right group.  Please feel free to 
redirect me :-)

I recently upgraded from CentOS 5.6 to 6.0.  Since the upgrade, Xvfb will, 
on occasion, "just stop" (ie the process disappears from the system,
as
opposed to still being there but not working).  I can't find any tracks 
anywhere that it might have left behind that might be clues as to why it 
stopped.  There's nothing in /var/log that looks promising (nothing in 
messages or Xorg.0.log).  

Any other clues about where to look or command line options I should add?  

Thanks in advance,

Bruce

From: bcb <bbowler at bigelow.org>
> I recently upgraded from CentOS 5.6 to 6.0.? Since the upgrade, Xvfb will, 
> on occasion, "just stop"
Maybe:
https://bugzilla.redhat.com/show_bug.cgi?id=498357

JD