NetApp and VMware vSphere Storage Best Practices

11 INCREASING STORAGE UTILIZATION
VMware provides an excellent means to increase the hardware utilization of physical servers. By increasing
hardware utilization, the amount of hardware in a data center can be reduced, lowering the cost of data
center operations. In a typical VMware environment, the process of migrating physical servers to virtual
machines does not reduce the amount of data stored or the amount of storage provisioned. By default,
server virtualization does not have any impact on improving storage utilization (and in many cases may have
the opposite effect).
By default in ESX 3.5, virtual disks preallocate the storage they require and in the background zero out all of
the storage blocks. This type of VMDK format is called a zeroed thick VMDK. VMware provides a means to
consume less storage by provisioning VMs with thin-provisioned virtual disks. With this feature, storage is
consumed on demand by the VM. VMDKs, which are created on NFS datastores, are in the thin format by
default.
With ESX 4.0. thin-provisioned VMDKs are now available to be created in the virtual infrastructure client with
VMFS datastores. By using VMware thin-provisioning technology, one can reduce the amount of storage
consumed on a VMFS datastore. VMDKs that are created as thin-provisioned disks can be converted to
traditional zero thick format; however, you cannot convert an existing zero thick format into the thinprovisioned
format.
NetApp offers storage virtualization technologies that can enhance the storage savings provided by VMware
thin provisioning. FAS data deduplication and the thin provisioning of VMFS datastores and RDM LUNs offer
considerable storage savings by increasing storage utilization of the FAS array. Both of these technologies
are native to NetApp arrays and don’t require any configuration considerations or changes to be
implemented within the ESX Servers.
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