Ann+1 redundantsystem has either two orthree power supplies,which may be inany slot.Note

Grid Redundancy

Thegrid redundant configuration is sometimes used when you have two power sources to power a chassis or
yourequire greater than N+1 redundancy. If one source fails (which causes a loss of power to one or two
powersupplies), the surviving power supplies on the other power circuit continue to provide power to the
chassis.A common reason for using grid redundancy is if the rack power distribution is such that power is
providedby two PDUsand youwant the grid redundancyprotection in the case of a PDU failure.
Toprovide grid redundant (or greater than N+1) protection, the following number of power supplies is
recommended:
•Fourpower supplies are recommended if the power configuration for that chassis requires greater than
2500Wor ifusing CiscoUCS Release1.4(1) and laterreleases
•Twopower supplies are recommended if the power configuration for that chassis requires less than
2500Wor thesystem is usingCisco UCS Release 1.3(1) or earlierreleases
Bothgrids ina power redundantsystem should have thesame number of powersupplies. If yoursystem
isconfigured for grid redundancy, slots 1 and 2 are assigned to grid 1 and slots 3 and 4 are assigned to
grid2. If thereare only two power supplies (PS) in the a redundant mode chassis, they should be in slots
1and 3. Slotand cord connection numbering is shown below.
Note
Figure 11: Power Supply Bay and Connector Numbering
PS1 PS2 PS3 PS 4
ServerSlot1 ServerSlot2
ServerSlot3
ServerSlot5
ServerSlot7
ServerSlot4
ServerSlot6
ServerSlot8
Front
Fan1 Fan2
I/OModuleSlot 1
I/OModuleSlot 2
Connector
PS4
Connector
PS3
Connector
PS2
Connector
PS1
Fan6
Fan5
Fan4
Fan3
Fan8
Fan7
Rear
279770
LEDs
LEDson both the chassis and the modules installed within the chassis identify operational states, both separately
andin combinationwith other LEDs.
Cisco UCS 5108 Server Chassis Installation Guide
OL-20035-05 23
Overview
LEDs