Owners Manual

PS4210 Hardware Owner's Manual
3 Maintaining Control Modules
Table 7: Control Module Status LED Descriptions
LED Name State Description
PWR
Off No power.
On (steady
green)
Power/OK.
ERR
Off Normal operation or no power.
Steady red
Array is starting up, in error condition, in Standby mode, or returning from Standby
mode.
Blinking red
Array is entering power standby mode because the Standby On/Off button was
pressed.
ACT
Off
No power, secondary control module is not synchronized with active control module,
or error condition.
Steady green
Active control module (serving network I/O).
Steady amber
Secondary control module. Cache is synchronized with active control module.
Identifying Control Module Failures
You can identify a failure in a control module by:
• LEDs on the control module itself. See Interpreting Drive LEDs on page 7.
• Messages on the console, in the event log, or in the Group Manager GUI Alarms panel.
• Group Manager GUI and CLI output. The Member Controllers window or the member select show
controllers command output shows the control module status not installed.
When viewed from the rear of the array, CM0 is on the top and CM1 is on the bottom. See Front-Panel Features
and Indicators on page 3.
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 (processing network I/O and performing storage
functions) at one time. Each control module stores 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 the network interfaces of the secondary control module for failover if a cable
is connected from the corresponding port on the secondary control module to a functioning network switch.
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
Ethernet 0 on CM0 loses connectivity (switch 0 fails), Ethernet 0 on CM1 cache is enabled and utilized. See
Dual Controller Configuration on page 16 for details.
• 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.
18