There's some ongoing threads at the Wiki entry: http://wiki.cloudstack.org/display/COMM/DevCloud?focusedCommentId=11829498#comment-11829498
Specifically, 1. On Mac OS X 10.6 (Snow Leopard), make sure you boot into the 64-bit kernel 2. Allocate more memory to the DevCloud VM 3. Reduce the memory usage for the JVM in dom0 Thanks -- Chiradeep
