dear All, I had a Centos 5.5 OS running for about 6 months used as a Xen VM server prfectly running 3 Virtual machines Its a Sun Blade server with 8 core Xeon Proceesor with 32 GB Ram couple of days back I added another 32 gb ram . The bios shows the added ram that is now it shows me 64 GB but the Centos OS just recognizes 32gb only the OS details are: Centos release 5.5 final Kernel 2.6.18-194.32.1.el5xen on an x86_64 now also running uname -a shows me Linux hypervisor2 2.6.18-194.32.1.el5xen #1 SMP Wed Jan 5 18:44:24 EST 2011 x86_64 x86_64 x86_64 GNU/Linux shows that PAE support is not there I do believe that installing kernel PAE with yum should solve the problem but since the server is a online production server just wanted to verify if I would run into some problems apprecite your kinf help and suggestions regards sylvan -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20110826/c6c7b0a3/attachment-0004.html>