198 The Green and Virtual Data Center
consolidated. Near-term physical hardware consolidation addresses PCFE
and associated costs; however, in the longer term, additional cost savings
can be obtained by addressing underutilized operating system images and
application software footprints.
On virtual servers or VMs, storage is typically presented as a virtual
SCSI disk. Virtual disks can be mapped to a local internal or external disk
or RAID volume, and can be on an iSCSI, Fibre Channel, FCoE, or Infini-
Band SAN, dedicated or shared SAS storage array as a raw LUN, or as a disk
file local or on NAS. For example, VMware supports a file system called
VMFS (VMware file system) for storing VMDK (VM virtual disks) with
snapshots, VMotion, or live migration or other ...