Maintaining Control Modules; Control Module Features; About Control Module Configurations - Dell EqualLogic PS4100 Hardware Maintenance Manual

3 Maintaining Control Modules

Different PS Series array models contain different control module types. The combination of chassis type,
control module pair, and drives determines the PS Series array model number.
The control modules in a PS Series array contain the PS Series firmware which provides the Group Manager
GUI, the Command Line Reference, and all the array and storage management functions and features.
Ideally, an array has two control modules (which must be of the same type) to avoid a single point of failure
for the array. A PS4100 array includes one or two hot-swappable Type 12 control modules.
One functioning control module is required for array operation. You access control modules from the rear
of the array.

Control Module Features

The Type 12 control module includes:
• Two 1G Ethernet ports, labeled Ethernet 0 and Ethernet 1 (each Ethernet port has two LEDs indicating
status and activity).
• One 10Mb/100Mbps port, labeled MANAGEMENT (for use only if you configure a management
network). The management port has two LEDs to indicate status and activity.
• A column of LEDs labeled PWR (power), ERR (error condition) and ACT (activity) that indicate the
status of the control module.
• A recessed button labeled STANDBY ON/OFF that allows you to quickly shut down the array in certain
circumstances (see
• One serial port (for use if there is no network access to the array).
• A field-replaceable microSD card containing the PS Series firmware.
• A release button and latch to release the control module from the array for replacement. The release
lever has a switch that detects activation and prompts the array to save data to non-volatile storage,
thereby protecting your data.
Do not mix control module types in an array. Always make sure both control modules are the same type and
color. See the latest PS Series Release Notes for information about other supported control modules.

About Control Module Configurations

While an array can run using only one control module, it is not recommended as this creates a single point
of failure. If the control module fails and there is no other to take over, all access to your volumes stops until
you replace it.
Only one control module is active (serving network traffic) at one time. The secondary (redundant) control
module mirrors cache data from the active control module. If the active control module fails, the secondary
will take over network operations.
About the Standby On/Off Button on page 21 for more information).
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