March 2013
Dell EqualLogic Configuration Guide v14.1
1-12
Figure 3
Controller failover process and optimal connection paths
1.4.4
Vertical port failover behavior in PS4100/PS6100 controllers
In PS Series controllers prior to PS4100/6100 families, a link failure or a switch failure was not
recognized as a failure mode by the controller. Thus a failure of a link or an entire switch would
reduce bandwidth available from the array. Referring to Figure 4 or Figure 5, assume that CM0 is the
active controller. In vertical port failover, if CM0 senses a link drop on the local ETH0 port connection
path, it will automatically begin using the ETH0 port on the backup controller (CM1). Vertical port
failover is bi-directional. If CM1 is the active controller then vertical port failover will occur from CM1
ports to CM0 ports if necessary.
