05-12-2017 01:58 AM - edited 05-12-2017 01:59 AM
We have a MX960 with 4x AC 250V Low Power Supplies. (3x1700W + 1 Redundancy)
Actual power allocated is 2695W. All power supplies share the load in zone0.
During maintenance window we need to shut the power of 2x power Supplies.
Are the 2x 1700W power supplies enough?
In my calculation the power budget is okay (3400W available, 2695W needed),
BUT Juniper documentation tells me different things
a) 3 power supplies for "non redundancy" and 4 power supplies for "3+1 redundancy"
b) another table shows me "minimum power supplies needed: 2
....I am confused!
05-13-2017 10:27 AM
We run with redundant 4 x high capacity power supplies so I've not done this directly. But the documentation seems pretty clear that when you use the normal capacity AC power supplies three are required. So I would say you need to gracefully shut down during this maintenance.
Normal-Capacity AC Power Supplies
The MX960 can be powered by three normal-capacity AC power supplies (non-redundant configuration) or four normal-capacity AC power supplies (redundant configuration). In a non-redundant configuration, the three AC power supplies share power almost equally within a fully-populated MX960 system. In a redundant configuration there is full power redundancy meaning if one power supply fails or is removed, the remaining power supplies instantly assume the entire electrical load without interruption and provide full power for the maximum configuration for as long as the router is operational.
Senior IP Engineer - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)
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