26 IntroductionPowerVault MD StorageThe controllers connect to the PowerVault MD iSCSI storage array, which is aRAID subsystem. RAID storage subsystems are designed to eliminate singlepoints of failure. Each active component in the storage subsystem isredundant and hot-swappable. The solution supports typical RAIDconfigurations including RAID 0, RAID 1, RAID 5, RAID 6, and RAID 10.BPSThe BPS provides continuous power to the controllers. Each controllerreceives its power from a dedicated BPS and from the power grid. Thecontrollers regularly monitor the BPS battery status, which requires the BPSto maintain a minimum level of power for normal operation. The BPS hassufficient battery power to allow the controllers to safely shut down.The BPS enables the controllers to use the cache as NVRAM. The BPSprovides the clustered solution enough time to write all the data from thecache to the disk if the controller experiences a loss of power.NOTE: You can view the BPS events on the NAS Manager.SAN NetworkThe SAN network is a critical part of the PowerVault NX3500 solution. Thecontroller pair that resides on the SAN network communicates to the storagesubsystem using the iSCSI protocol. The PowerVault NX3500 communicateson the SANa and SANb networks, rendering a high availability (HA) design.Internal NetworkThe PowerVault NX3500 solution requires an internal network for peer-to-peer data transfer and management. To achieve complete data distributionand to maintain HA, each controller must have access to its peer controller.The internal network achieves this goal.The internal network is classified into internal network A and internal network B.NOTE: Ensure that the IP addresses you assign to internal network A and internalnetwork B are from a private IP space and do not conflict with other subnets onyour network.
