A controller tray contains two redundant array of independent disks (RAID) controllers, which operate independently and provide failover capability for the management path. The controller tray is configured for Fibre Channel (FC) disk drives and provides RAID functionality, caching, and disk storage.
The RAID controller has 1 gigabyte of memory for processor memory and data cache. The processor memory is used to store application data, while the data cache is a buffer used to store data temporarily during data read and write functions.
Each controller contains a sealed, rechargeable 4-volt, lead acid battery. This battery provides backup power to cache memory for up to three days in the event of a power loss. You must replace the battery every two years.
The controller tray has the following components:
Light emitting diodes (LEDs) and switches on the front of the controller tray are available to monitor the state of the controller. The ports, switches, and LEDs at the back of the controller tray also enable you to monitor state of the controller and are especially useful during installation.
The front view of the controller tray is as follows: