Dell PowerVault MD1200 - Manual (Page 16)

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About Your Enclosure
Enclosure Failover When Two EMMs are Installed
If two EMMs are installed, a certain degree of failover is offered. Control and
monitoring of the enclosure elements can be transferred from one EMM to
another in the event of an EMM failure. A failover occurs whenever
communication is lost between an EMM and its peer.
In the event of a peer EMM failure, the surviving EMM activates the amber
status LED of the failed EMM. The surviving EMM then takes over the
responsibility of enclosure management, which includes monitoring and
control of the audible alarm, enclosure LEDs, power supplies, and fans.
Failover does not include providing connectivity to the drives controlled by
the failed EMM. When a failed EMM is replaced, enclosure management
functions do not automatically return to the replaced EMM unless an
additional failure occurs that triggers another failover event. The new EMM
only restores the data path to the hard drives controlled by the failed EMM.
EMM Thermal Shutdown
If critical internal temperatures are reached, the enclosure shuts down
automatically through either a thermal shutdown command issued by the
EMM firmware or through a command from Dell™ OpenManage™ Server
Administrator.
Enclosure Alarms
An audible alarm is activated if any of the fault conditions listed below occur.
The alarm sounds continuously if:
• More than one fan has failed or a power supply/cooling fan module is not
installed.
• One or more temperature sensors are in critical range.
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