Dell EqualLogic PS6610E EqualLogic PS6610 Storage Arrays Hardware Owners Manua - Page 24

PS6610 Hardware Owner's Manual 3 Control Module Maintenance LED Name State Off Steady red ERR Blinking red PWR Off On (steady green) Description Normal operation or no power Array is starting up, in error condition, in Standby mode, or returning from Standby mode. Array is entering power standby mode because the Standby On/Off button was pressed. No power Power/OK Identify Control Module Failures You can identify a failure in a control module by: • LEDs on the control module itself. See Interpreting Control Module LEDs on page 16. • 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 left and CM1 is on the right. If a control module fails, contact your PS Series support provider for a replacement. About 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. 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 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. 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 on circumstances, network I/O might instead continue through the previously active control module. (For example, the control module that becomes active can use either its own local network interface, or the network interface on the previously active control module.) 18