[PlanetCCRMA] A few FC3 questions

[Spec]

1. How do I remove an LVM volume (and LVM entirely...). Its a pain, 
because it appears to have filled up the HDC1 partition (entire disk) 
before it fills the HDA2 partition (HDA1 being boot I guess). looking at 
lvdisplay and pvdisplay shows this.

2. Is it worth having the GDM
  a) I want to log straight in to xfce, dont mind using startx to do 
that without
      any graphical user interface.
  b) is there any security advantage to using gdm?

3. getting this error when loading qjackctl in xfce, I dont get it running
qjackctl under gnome, that starts jackd OK (no errors)???

error occurs only in xfce

 > cannot write to jackstart sync pipe 4 (Bad file descriptor)
 > jackd: wait for startup process exit failed

It then says loaded OK and appears to work without xruns where under gnome
xruns would appear.  (I do get xruns under xfce running at ultra low 
latency
<1ms so the comms for xrun messges is working)

does it require some service (dbus/messagebus perhaps) I have stopped?
Or... does it (jackd and thus jackstart) just start up too fast to be 
attached to under xfce?  (could be?)
Or ...is it some other problem?