Fibre Channel Architecture

Overview

The Sun StorEdge 3510 FC array RAID controller has six fibre channels that can support 1 or 2 Gb data transfer speeds. RAID controller channels 0, 1, 4, and 5 are normally designated for connection to hosts or Fibre Channel switches. RAID controller channels 2 and 3 are dedicated drive channels.

In a dual RAID controller configuration, both RAID controllers have the same host channel designators, due to the architecture of the loops within the chassis. Each host channel of the top RAID controller shares a loop with the matching host channel on the bottom RAID controller. For example, channel 0 of the top RAID controller shares the same loop as channel 0 of the bottom RAID controller. This provides four distinct loops for connectivity with two ports per loop. The individual loops provide LUN failover without causing HBA path failover in the event of a controller failure.

Each I/O board has two ports designated as disk drive loops. These ports connect to the internal dual-ported Fibre Channel disk drives and are used to add expansion chassis to the configuration. The two drive loop ports on the upper I/O board form FC loop 2 while the two drive ports on the lower I/O board form FC loop 3. FC loop 2 provides a data path from both RAID controllers to the A loop of the internal disk drives, while FC loop 3 provides a data path from both RAID controllers to the B loop of the internal disk drives.

A single RAID controller configuration is slightly different. The lower I/O board has drive channels but does not have host channels. Overall, the same number of loops are available, but with half as many host channel ports.

Fibre Channel Protocols

The Sun StorEdge 3510 FC array supports point-to-point and Fibre Channel– Arbitrated Loops (FC–AL) protocols. Using the point-to-point protocol with the Sun StorEdge 3510 FC array requires a switched fabric network (SAN), whereas selecting FC-AL mode enables the array to be used in either DAS or SAN environments. Using point-to-point protocol enables full-duplex use of the available channel bandwidth, whereas selecting FC-AL mode limits host channels to half-duplex mode.

Best Practices for the Sun StorEdge 3510 FC Array 3