The use of NAS heads imposes a new set of considerations on the backup and recovery strategy in NAS environments. NAS heads use a proprietary operating system and file system structure supporting multiple file-sharing protocols. In the NAS environment, backups can be implemented in four different ways: server based, serverless, or using Network Data Management Protocol (NDMP) in either NDMP 2-way or NDMP 3-way.[ NDMP is an industry-standard TCP/IP-based protocol for moving data across the network for backup and recovery. It can communicate with several interfaces for data transfer and enables vendors to use a common protocol for the backup architecture. Data can be backed up using NDMP regardless of the operating system or platform. Due to its flexibility, it is no longer necessary to transport data through the backup server, which reduces the load on the backup server and improves backup speed.]

In application server-based backup, the NAS head retrieves data from storage over the network and transfers it to the backup client running on the application server. The backup client sends this data to a storage node, which in turn writes the data to the backup device. This results in overloading the network with the backup data and the use of production (application) server resources to move backup data.

Figure illustrates server-based backup in the NAS environment.

In serverless backup, the network share is mounted directly on the storage node. This avoids overloading the network during the backup process and eliminates the need to use resources on the production server. Figure illustrates serverless backup in the NAS environment.

In this scenario, the storage node, which is also a backup client, reads the data from the NAS head and writes itto the backup device without involving the application server. Compared to the previous solution, this eliminates one network hop.