Release Notes

Building a high-availability SAN
54 Dell PS Series Configuration Guide
9.7 Vertical port failover behavior in PS4210/PS6210/PS6610
controllers
In PS Series controllers prior to PS4110/6110/6210 families, a link failure or a switch failure was not
recognized as a failure mode by the controller. This caused a failure of a link or an entire switch to reduce
bandwidth available from the array. Referring to Figure 13, 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.
Note: The vertical port failover behavior exhibited in PS4210/PS6210 controllers also applies to the PS6610.
PS6210 vertical port failover
For more information about vertical port failover, see the PS4210 Hardware Owner’s Manual or PS6210
Hardware Owner’s Manual or PS6610 Hardware Owner’s Manual at
https://eqlsupport.dell.com/support/resources.aspx?id=2495 (requires support login). With the
PS4210/PS6210/PS6610 family of controllers, vertical port failover can ensure continuous full bandwidth is
available from the array even if you have a link or switch failure. This is accomplished by combining each
10GbE “eth0” and “eth1” ports in each controller into a single logical port from the point of view of the active
controller. In a fully redundant SAN configuration, you must configure the connection as shown in Figure 18.
In a redundant switch SAN configuration, to optimize the system response in the event you have a vertical
port failover you must connect either the SFP+ cable or the 10GbaseT cable from each controller to a
different switch in the SAN network. While it is a supported configuration, it is not recommended to connect
both the SFP+ and 10GbaseT ports on each controller at the same time. In this scenario, the SFP+ port will
always be the preferred active port and this preference cannot be changed by the user. This preference is not
guaranteed in future array firmware releases.
The connection paths illustrated in Figure 18 show how to connect the port connection paths between the two
controllers. Also note how IP addresses are assigned to the vertical port pair.