If you are using to use dbms_dnfs to clone your database as described in MOS note 1210656.1 or on Tim's Hall blog - Direct NFS (DNFS) Clonedb in Oracle Database 11g Release 2 (Patchset 11.2.0.2) and your database version is 11.2.0.3 there is one additional step which is not covered by clone.pl script and has to be done manually.
This story begins couple of weeks ago when I was asked to look on performance problem for critical processes before go-live. There were differences between run times between different test systems and between runs with 10046 trace enabled or not.
I'm still quite new in Vmware ESX environment and features which I'm using now as my lab (curiosity of VMWare Guru Program). This time I decided to test hot add CPU and memory functionality. It looks very interesting and in past years hot cpu / memory games where restricted to sophisticated hardware only - now everybody can test is at home.