NAS implementations:

• There are two types of NAS implementations: integrated and gateway. The integrated NAS device has all of its components and storage system in a single enclosure (package). In gateway implementation, NAS head shares its storage with SAN environment.

  1. Integrated NAS:

  • An integrated NAS device has all the components of NAS, such as the NAS head and storage, in a single enclosure, or frame. This makes the integrated NAS a self-contained environment. The NAS head connects to the IP network to provide connectivity to the clients and service the file I/O requests. The storage consists of a number of disks that can range from low-cost ATA to high throughput FC disk drives. Management software manages the NAS head and storage configurations.

  • An integrated NAS solution ranges from a low-end device, which is a single enclosure, to a high-end solution that can have an externally connected storage array.

  • A low-end appliance-type NAS solution is suitable for applications that a small department may use, where the primary need is consolidation of storage, rather than high performance or advanced features such as disaster recovery and business continuity. This solution is fixed in capacity and might not be upgradable beyond its original configuration. To expand the capacity, the solution must be scaled by deploying additional units, a task that increases management overhead because multiple devices have to be administered.

  • In a high-end NAS solution, external and dedicated storage can be used. This enables independent scaling of the capacity in terms of NAS heads or storage. However, there is a limit to scalability of this solution.

    

  2. Gateway NAS:

  • A gateway NAS device consists of an independent NAS head and one or more storage arrays. The NAS head performs the same functions that it does in the integrated solution; while the storage is shared with other applications that require block-level I/O. Management functions in this type of solution are more complex than those in an integrated environment because there are separate administrative tasks for the NAS head and the storage. In addition to the components that are explicitly tied to the NAS solution, a gateway solution can also utilize the FC infrastructure, such as switches, directors, or direct-attached storage arrays.

  • The gateway NAS is the most scalable because NAS heads and storage arrays can be independently scaled up when required. Adding processing capacity to the NAS gateway is an example of scaling., adding capacity on the SAN independently of the NAS head. Administrators can increase performance and I/O processing capabilities for their environments without purchasing additional interconnect devices and storage. Gateway NAS enables high utilization of storage capacity by sharing it with SAN environment.