NetApp active/active storage controller configuration

I have connected new disk shelf to the john keels SAN.So I learn about how to loop them and use the method multi-path storage.The controlling node was a 3050 controller.
Each of the two identical storage controllers within the active/active configuration serves data independently during normal operation, but in the event of individual storage controller failure, the data service process transfers from the failed storage controller to the surviving
partner(work also in hardware failures).

The active/active controller configuration consists of a pair of matching FAS storage controllers (local node and partner node); each of these nodes must be connected to the other’s disk shelves.The Data ONTAP and interconnect adapters on each node must be identical and configured with the same firmware version.Data ONTAP on each node monitors the availability status of its partner by means of a heartbeat signal transmitted between the storage controllers,then stores this information on specialized mailbox disks.The NVRAM data of each controller node is always mirrored on the partner node.Only half of the NVRAM in the controller is dedicated to the local node,other half reserves for the partner node’s data to ensure that exactly the same data exists in NVRAM on both storage controllers. If fail over occurs, when the surviving node takes over the failed node, all WAFL checkpoints stored in NVRAM are flushed to disk. The surviving node then combines the split NVRAM and recovers the lost performance.
Once the surviving node restores disk control and data processing to the recovered failed node, all NVRAM data belonging to the partner node is flushed to disk during the course of the giveback operation.

Active controller configuration methods

1.standard active controller
2.active controller with syncmirror
3.Metro cluster
4.Multi-path HA storage

Multi-path HA storage

The Multi path HA Storage solution significantly improves data availability and performance consistency by providing multiple redundant paths to the storage shelves.This prevents fail overs and increase bandwidth of shelves.Multipath support is provided with Data ONTAP 7.1.1, 7.2.1, and higher(FAS3050 supports but FAS270c is not).Here Primary and secondary loops must use separate Fiber Channel adapters.Storage shelves must be equipped with controller modules providing auto-termination functionality(ESH2).Also we have to set software-based disk ownership (SANOWN).
NetApp storage controllers and disk shelves are equipped with redundant power supply modules. By connecting each of the two power supplies within a device to separate power circuits or PDUs (power distribution units), devices are protected from single circuit power failures.