Sun Microsystems 3900 Series manual Sun StorEdge 6900 Series Multipathing Example

Sun StorEdge 6900 Series Multipathing Example

One Sun StorEdge T3+ array partner pair with 1 500GB RAID 5 LUN per brick (2 LUNs total)

Currently, there is one 10GB VLUN created from each physical LUN, for a total of two VLUNs. In a Sun StorEdge 6900 series, there are four possible physical paths to each Sun StorEdge T3+ array Volume (LUN). Refer to FIGURE 7-4and FIGURE 7-3.

For example, to access the LUN on the Alt-Master, the Sun StorEdge T3+ array I/O could travel:

■From HBA-0 -> Switch -> SVE(1) -> Switch -> Alt-Master Controller (Primary Route from HBA-0)

■From HBA-0 -> Switch -> SVE(1) -> Switch -> Switch -> Master Controller -> Backend Loop to Alt-Master (Secondary Route from HBA-0)

■From HBA-1 -> Switch -> SVE(2) -> Switch -> Switch -> Alt-Master Controller (Primary Route from HBA-1)

■From HBA-1 -> Switch -> SVE(2) -> Switch -> Master Controller -> Backend Loop to Alt-Master (Secondary Route from HBA-1)

The virtualization engine recognizes the primary (active) and secondary (passive) pathing for the LUNs and routes the I/O to the primary controller, unless there is a pathing failure to the primary path. In this case, the virtualization engine initiates a LUN failover and routes the I/O through the secondary path (which, in turn, goes through the interconnect cables). Refer to FIGURE 7-6.

The host, using multipathing software, is presented two primary (active) paths for each LUN, allowing the host to route I/O through either or both HBAs.

In the event of a path failure before the second tier of Sun StorEdge network FC switch-8 and switch-16 switches (refer to FIGURE 7-5), one of the paths is disabled, but the other path continues sending I/O as normal and takes over the entire load. No Sun StorEdge T3+ array LUN failure is noted because of the redundant path by way of the Sun StorEdge network FC switch-8 and switch-16 switch T Ports.

Chapter 7 Troubleshooting Virtualization Engine Devices 89

For Internal Use Only