Go easy as I'm new to both Nginx and VPS Admin :)
I've previously got Apache and Varnish running on a few virtual sites on a new 1G VPS.
I've read a pile of stuff on the virtues of Nginx and especially the great work on this site so I've started migrating across to Nginx.
Just so I can come to grips with Nginx and keep my main site running with little downtime, I'm running both Apache and Nginx behind Varnish. The webservers are using different ports and I've configures Varnish to bypass the domains that are running Nginx. Not ideal but once I have got the initial Nginx installs and configs running OK, I'll be deactivating both Apache and Varnish.
 I'm really unsure how I go about replacing the Nginx 1.4.3-1 packages that VirtualMin installed on my VPS so I can get the recommended one that contains cache-purging. Installed packages are:
nginx 1.4.3-1~precise0 nginx-common 1.4.3-1~precise0 nginx-full 1.4.3-1~precise0
All I get when I try is an error: The following packages have unmet dependencies: nginx-custom : Depends: nginx-common (= 1.4.1-0ppa~precise) but 1.4.3-1~precise0 is to be installed E: Unable to correct problems, you have held broken packages.
Possible to give me the step-by-step baby steps for a newbie to remove whatever needs removing and installing what needs to be installed please?
=================  I do have Nginx limping along however I notice that for my 2 test sites, there are instances of large php5s running i.e. site1 313080 kB /usr/bin/php5-cgi -b /var/php-nginx/137928790532167.sock/socket site2 284292 kB /usr/bin/php5-cgi -b /var/php-nginx/137928596329458.sock/socket
Is this normal or have I got something misconfigures as I would have imagined things would be leaner and meaner than this fat old php5 running?
================= Thank you heaps for any and all help too. Appreciate any efforts to help an old dude :) Martin