Enclosure Failover When Two Emms Are Installed; Emm Thermal Shutdown; Power Supply And Cooling Fan Features - Dell PowerVault MD1120 Hardware Owner's Manual

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 and holds it in reset. 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 physical disks
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, or the
enclosure is power cycled.

EMM Thermal Shutdown

If critical internal temperatures are reached, the enclosure will be shut down
automatically via either a thermal shutdown command issued by the EMM
firmware or via a command from Server Administrator.

Power Supply and Cooling Fan Features

Your storage enclosure supports two integrated, hot-pluggable power
supply/cooling fan modules. Each module contains four separate cooling fans.
Both modules must be installed to ensure proper cooling. The enclosure
requires at least seven of the individual cooling fans to operate to avoid
overheating.
CAUTION:
A power supply/cooling fan module can be removed from a powered-
on enclosure; however, the enclosure will shut down if overheating occurs.
A power supply/cooling fan module can be replaced without powering down
the enclosure. For information on removing and replacing the modules, see
"Removing and Installing the Power Supply/Cooling Fan Module" on page 35.
Figure 1-7 shows the power supply/cooling fan module features and LED
indicators. Table 1-5 lists the LED indicator descriptions.
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