Unified Storage — More Than Just SAN/NAS

By David Hubbard, CEO, RELDATA

At the enterprise level, FC SANs can be used as a base on which to build NAS storage silos, providing a form of unified storage architecture. However, in reality there are still two separate systems to manage: The FC SAN and the NAS head. Low cost flexibility is also a phrase that few will associate with a virtualized FC SAN. While the basic costs of FC SAN have dropped in recent years, try adding in additional hosts, remote sites and backup, and the costs escalate dramatically. Add to this the need for FC networking skills and it is clear that this is no mass-market solution.

At the other end of the scale, NAS vendors have bolted iSCSI functionality on top of their file system. Again, this is a form of unified storage architecture. But the reality is that pushing IP SAN application storage through a file system is like driving a Ferrari in a traffic jam: it does not actually go any faster. Add a file system crash into the equation, and recovering block storage that was running over the top of NAS can get really nasty.

The only area which has seen genuine advances for the SME customer is pure iSCSI SAN. IP SAN really can offer lower hardware costs and deliver flexible connectivity for new storage hosts, new capacity and remote sites, and dramatically simplify backup. And, the vendors that have succeeded in the IP SAN space are those who have developed simple, well-defined GUIs that actually deliver these benefits to the administrator.