The default i/o scheduler is the Completely Fair Queuing (cfq) in the 2.6 kernel. This is not the first choice for a virtual machine/hypervisor. The combination of the noop and the deadline scheduler is much better for a virtualization host.

virtual machine: noop
hypervisor: deadline

Set the …

To create a shared disk between two or more VMs, login into one of your ESX hosts and create a disk image.

cd /vmfs/volumes/#volume-name#/#vm-name#/;
vmkfstools -d thick -a lsilogic -c 50G shareddisk.vmdk;

Add the new hardrive to the guest(s) and select a new SCSI bus …