Release Notes

Building a high-availability SAN
46 Dell PS Series Configuration Guide
9.4 Basic controller failover behavior in all models
To support redundant controller fail over, each Ethernet port on the active controller that is connected to the
SAN must have its corresponding port on the passive controller also connected to the same SAN network. In
the event of a controller failure, the passive controller will immediately activate and continue to process all
data requests to the array. The following changes occur during fail over:
• The backup controller automatically enables each of the corresponding Ethernet ports that were
enabled on the failed primary controller
• The IP addresses that were assigned to each of the failed controller Ethernet ports are reassigned to
the corresponding ports on the second controller.
9.4.1 Basic controller failover for models prior to PS4100/PS6100
A link failure on one or more of the Ethernet ports on the active controller does not constitute a controller
failure. For this reason, it is important to ensure that ports from each controller are connected to at least two
different switches. This will prevent a switch failure from also disabling all paths between a host and its
connected volumes.
It is also critical that port connections for both controllers are configured so that the corresponding ports on
each controller are connected to the SAN. If port 0 on the active controller is the only port connected to the
SAN, then you must use port 0 on the passive controller for the other connection to the SAN. This is
illustrated in the partially connected scenario shown in Figure 9.
Partially connected controller failover