S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
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Cisco MDS 9000 Family CLI Configuration Guide
OL-16184-01, Cisco MDS SAN-OS Release 3.x
Chapter 10 Managing System Hardware
Power Supply Configuration Modes
b.
Combined mode—the total power is twice the lesser of the two power supply capacities.
For example, suppose you have the following usage figures configured:
Power supply 1 = 2500 W
Additional Power supply 2 = not used
Current Usage = 2000 W
Current capacity = 2500 W
Then, the following three scenarios differ as specified (see
Table 10-2
):
Scenario 1:
If 1800 W is added as power supply 2, then the capacity increases to 3600 W.
Reason:
3600 W is twice the minimum (1800 W).
Scenario 2:
If 2200 W is added as power supply 2, then the current capacity increases to 4400
W.
Reason:
4400 W is twice the minimum (2200 W).
Scenario 3:
If 3000 W is added as power supply 2, then the current capacity increases to 5000
W.
Reason:
5000 W is twice the minimum (2500 W).
2.
When you change the configuration from combined to redundant mode and the system detects a
power supply that has a capacity lower than the current usage, the power supply is shut down. If both
power supplies have a lower capacity than the current system usage, the configuration is not allowed.
Several configuration scenarios are summarized in
Table 10-3
.
Scenario 1:
You have the following usage figures configured:
Power supply 1 = 2500 W
Additional Power supply 2 = 1800 W
Current Usage = 2000 W
Current mode = combined mode (so current capacity is 3600 W)
Table 10-1
Redundant Mode Power Supply Scenarios
Scenario
Power
Supply 1
(W)
1
1.
W = Watts
Current
Usage
(W)
Insertion of
Power
Supply 2 (W)
New
Capacity
(W)
Action Taken by Switch
1
2500
2000
1800
2500
Power supply 2 is shut down.
2
2500
2000
2200
2200
Capacity becomes 2200 W.
3
2500
2000
3300
2500
Capacity remains the same.
Table 10-2
Combined Mode Power Supply Scenarios
Scenario
Power
Supply 1
(W)
1
1.
W = Watts
Current
Usage
(W)
Insertion of
Power
Supply 2 (W)
New
Capacity
(W)
Action Taken by Switch
1
2500
2000
1800
3600
Power is never shut down. The
new capacity is changed.
2
2500
2000
2200
4400
3
2500
2000
3300
5000
