Comment 23 for bug 1433329

(In reply to Bastiaan Jacques from comment #19)
> (In reply to Hans de Goede from comment #5)
> > For use with startx it requires a tiny bit of manual configuration (because
> > otherwise various dm-s would be broken), see:
> > http://hansdegoede.livejournal.com/14446.html
>
> I've followed these instructions on several machines and it seems to work
> well, in that `ps' shows Xorg.bin running as the user that started it,
> except for the following.
>
> If I understand correctly, it should be possible for several users, or a
> single user, to run multiple X servers simultaneously without root
> privileges. But this doesn't work on two systems that I've tried, using
> startx, logging output:
>
> [1650443.633] _XSERVTransSocketUNIXCreateListener: ...SocketCreateListener()
> failed
> [1650443.634] _XSERVTransMakeAllCOTSServerListeners: server already running
> [1650443.634] (EE)
> Fatal server error:
> [1650443.634] (EE) Cannot establish any listening sockets - Make sure an X
> server isn't already running(EE)
> [1650443.634] (EE)
> Please consult the Fedora Project support
>
> Am I missing something?

You should be able to do what you want by starting the 2nd xserver like this:

startx -- :1

And the 3th:

startx -- :2

etc.