32 Planning: RAID Controller ModulesRAID Controller Module—Additional FeaturesBattery Backup UnitEach RAID controller contains a two-cell lithium ion nanopolymer batterybackup unit (BBU). It provides power to the RAID controller module in theevent of a power outage, see "RAID Controller Module Backup Battery Unit"on page 202.NOTE: For virtual disks, the RAID controller firmware changes the data cachesetting based on the state of the battery. If the battery is missing or does not havesufficient charge, the controller flushes the cache and sets the write cacheattribute to Write Through for all virtual disks. When the battery is replaced, WriteBack is re-enabled.18 SAS IN 3 portlink/fault LEDLights green when all four links are connected.Lights amber when one to three links are disconnected.Off when all links in the port are disconnected or cable isdisconnected.19 Managementport speed LEDLights green when ethernet connection is operating at 1000Mbps.Lights amber when ethernet connection is operating at 100Mbps.Off when ethernet connection is operating at 10 Mbps or isnot active.20 Managementport activity LEDLights green when ethernet connection is active.Off when ethernet connection is not active.21 Managementport EthernetconnectorProvides a 100/1000 Mbps Ethernet connection for out-of-band management of the enclosure.Item Component Function
