PowerVault ME5 arrays support SAN-attached Fibre Channel (16/32 Gb) and iSCSI (10/25Gb) connectivity. A switch-attached solution (or SAN) places a Fibre Channel or Ethernet switch between the servers and the controller enclosures within the storage system. Using switches, a SAN shares a storage system among multiple servers reducing the number of storage systems required for a particular environment. Using switches increases the number of servers that can be connected to the storage system to scale to greater than four servers, which is the limit for a direct-attached environment.
When designing a SAN, we recommend using two switches. This practice enables you to create a redundant transport fabric between the server and the PowerVault ME5 storage. This configuration also allows you to take an individual switch out of service for maintenance, or due to failure, without impacting storage-access availability.
When cabling the PowerVault ME5 controllers in a switched environment, pay close attention to the layout of the cables in both Fibre Channel and Ethernet fabrics. In the following figure, controller A (the left-most PowerVault ME5084 controller) has ports 0 and 2 connected to the top switch, and ports 1 and 3 are connected to the bottom switch. This configuration repeats in a similar fashion with controller B. The servers are configured with each server having connections to each switch. This cabling ensures that access to storage remains available between an individual server and the PowerVault ME5 array during switch maintenance.