Dell EqualLogic PS4110 Hardware Owner's Manual page 25

Hardware Owner's Manual
• Group Manager GUI and CLI output. The Member Controllers window or the
command output shows the control module status
trollers
When viewed from the rear of the array, CM0 is on the top, and CM1 is on the bottom. See
Features and Indicators on page
If a control module fails, contact your PS Series support provider for a replacement.
Understanding Failover Behavior
In a dual control module array, only one control module is active (serving network traffic) at one time. Each
control module includes a cache-to-flash module for storing recently-used data.
For redundancy, the cache on the secondary control module mirrors the data that is stored in the cache on the
active control module.
The active control module can use a network interface on the secondary control module if there is a cable
connected from the corresponding port on the secondary control module to a network switch.
Note: The management ports on the control modules do not fail over if one control module fails. Therefore, if
you are using a dedicated management network, make sure the management ports on both control modules are
connected to the management network.
A PS Series array provides the following types of network failure protection:
• Vertical failover. In a dual control module array, a network port on the active control module can fail over
to the same network port on the other (secondary) control module if a network path fails. For example, if Eth-
ernet 0 on CM0 loses connectivity (switch 0 fails), Ethernet 0 on CM1 takes over.
figuration" on page 18
• Control module failover. In a dual control module array, if the active control module fails, the secondary
control module automatically takes over and becomes active.
If a cable is connected to a network port on the newly-active control module, network I/O can switch to its
network interface. Depending upon circumstances, network I/O may instead continue through the previously
active control module. (i.e. The control module that becomes active can use either its own local network
interface, or the network interface on the previously-active control module.)
Control module failover is transparent to applications, but iSCSI initiators must reconnect to the group IP
address.
Maintaining Control Module Firmware
A control module has a microSD card running the array firmware. You should run the latest firmware version to
take advantage of new product features and enhancements.
3.
for details.
3 Maintaining Control Modules
member select show con-
.
not installed
See "Dual Controller Con-
Front-Panel
21