NetApp and VMware vSphere Storage Best Practices

Figure 43) Storage consumption after enabling FAS data deduplication.
Deduplication is enabled on a volume, and the amount of data deduplication realized is based on the
commonality of the data stored in a deduplication-enabled volume. For the largest storage savings, NetApp
recommends grouping similar operating systems and similar applications into datastores, which ultimately
reside on a deduplication-enabled volume.
Note: whether one enables data deduplication or not has no impact in terms of the number of VMs which
reside on a datastore. One should size a datastore density as one would without deduplication.
DEDUPLICATION CONSIDERATIONS WITH VMFS AND RDM LUNS
Enabling deduplication when provisioning LUNs produces storage savings. However, the default behavior of
a LUN is to reserve an amount of storage equal to the provisioned LUN. This design means that although
the storage array reduces the amount of capacity consumed, any gains made with deduplication are for the
most part unrecognizable, because the space reserved for LUNs is not reduced.
To recognize the storage savings of deduplication with LUNs, you must enable NetApp LUN thin
provisioning. For details, see section 7.2, “Storage Thin Provisioning.” In addition, although deduplication
reduces the amount of consumed storage, the VMware administrative team does not see this benefit
directly, because their view of the storage is at a LUN layer, and LUNs always represent their provisioned
capacity, whether they are traditional or thin provisioned.
DEDUPLICATION CONSIDERATIONS WITH NFS
Unlike with LUNs, when deduplication is enabled with NFS, the storage savings are both immediately
available and recognized by the VMware administrative team. No special considerations are required for its
usage.
For deduplication best practices, including scheduling and performance considerations, see TR-3505:
NetApp FAS Dedupe: Data Deduplication Deployment and Implementation Guide.
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