Temperature probes – Dell PowerVault 220S (SCSI) User Manual
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Introduction: Dell PowerVault 220S and 221S Systems User's Guide
file:///C|/Users/rishi_sood/Desktop/220s/en/ug/8f182c11.htm[3/7/2013 12:09:43 PM]
Management functions — Includes SES and SAFTE reporting to the host initiator, control of all enclosure LED indicators,
and monitoring of all enclosure environmental elements such as temperature sensors, cooling modules, and power
supplies.
A system with redundant enclosure management features two EMMs that are designated as primary and secondary and that
can be configured in either a cluster, joined-bus, or split-bus mode. A nonredundant configuration consists of one EMM and
one SCSI terminator card, and can be configured only in a joined-bus mode. In a redundant system, only one EMM per SCSI
bus is active at one time, so only one EMM per SCSI bus can respond to SCSI commands from an initiator.
In joined-bus and cluster modes, if a secondary EMM receives a message that the primary EMM has failed, the fault LED
indicator on the primary EMM is illuminated and the condition is reported back to the host initiator. The secondary EMM will
then become active and hold the failed primary in a state of reset until it is replaced. If the primary EMM detects that the
secondary has failed, the secondary's fault LED indicator is illuminated and the failed status is reported back to the host
initiator.
NOTE:
In split-bus mode, each EMM controls half of the enclosure. If one EMM fails in split-bus mode, the second EMM
will report the failure, but will not assume control of the entire SCSI bus.
The primary EMM is always plugged into the slot on the left (viewed from the back of the system). In a redundant joined-bus
configuration, the primary EMM assumes control of all enclosure functionality. In addition, the primary EMM is the only module
that reports status of the system to the host initiator through SES and SAFTE protocols. Because the secondary EMM must
assume the responsibilities of the primary in the event that the primary fails, both the primary and secondary EMMs are
continuously monitoring the status of the system's components.
EMM LED Indicators
lists the functions of each EMM LED indicator. See
for the location of the indicator LEDs.
NOTE:
If you have a nonredundant system with only one EMM installed, the only indicators that function are the power
LED and active LED indicators.
Table 1-5. EMM LED Indicators
LED Indicator LED Icon Condition
Power (green)
The system is receiving power.
Fault (amber)
An EMM has failed.
Active (green)
The EMM is operating normally.
Temperature Probes
Your system contains four temperature probes that monitor system temperature and shut down the system in the event of
overheating. Each EMM and both the primary and secondary backplanes contain temperature probes.
identifies the
location of each probe.
Table 1-6. Temperature Probe Locations
Probe
Location
Probe 0 Primary EMM
Probe 1 Secondary EMM
Probe 2 Drive backplane behind drive ID #3
Probe 3 Drive backplane behind drive ID #13