Like many others, we are running into issues with Oracle licensing. Oracle charges a lot for its software and using state-of-the-art hardware you may even end up paying more, rather than less. The thing is, Oracle refuses to see VMware virtualization as "hard partitioned" but instead as "soft partitioned". That is, a single core VM may run on all cores that are available to it. So Oracle licensing requires you to factor in every core. Oracle's own Oracle VM (OVM) for x86 and SPARC (Xen-based) uses hard partitioning, but this comes at the cost of loss of overcommitment. That is, you cannot assign more cores than you have and increase the CPU utilization of your hosts. This is not necessarily bad, but means you can run less VMs on a given host. Reference: Oracle Storage Guy and Weinshenker.net
Blog about usage of Oracle's Enterprise Linux (OEL) aka "Unbreakable Linux" in a data center. Installation, configuration, tweaks, hacks, tips and tricks... whatever and all of the above, as we deploy Linux servers as the choice for all non-Microsoft services