Using the public cloud as a NAS tier for primary storage is a much tougher sell for most IT shops than for backups or archives. However, an emerging technology that could make the prospect more pleasant is the gateway that acts as a hybrid cloud storage appliance.
The appliances supply an on-premises cache that can provide access to the most active or frequently accessed data, hence network or cloud outages do not prevent users from getting needed files.
Most of the appliances also offer deduplication to reduce bandwidth consumption and lower the fees associated with transferring data to and from the cloud. They encrypt the data before sending it off-premises and offer snapshots to lighten the load on backup systems.
Several startups currently rule the roost in the NAS hybrid cloud space and typically partner with prominent cloud storage providers.
It is understood that major NAS vendors such as EMC or NetApp will eventually provide the protocol support for a cloud tier in addition to their SSDs and SATA and SAS drives.