Ultra-Dense Server Deployment in Racks

Compaq Ultra-Dense Server Deployment in Compaq Racks 18
128H-0400A-WWEN
This de-rated input power budget significantly reduces the power and thermal requirements for highly
populated racks. This can mean reduced number of PDUs for certain configurations illustrated in Section
3. Fewer PDUs translates to faster deployment time and lower cost. This can also mean reduced costs for
the facility electrical plumbing, data center floor ventilation, and facility air conditioning installation.
However, care must be taken in de-rating the input power budget.
Note: Compaq strongly recommends the installation planner to ensure that the de-rated power budget will
satisfy all the installation requirements, including future upgrade plans.
When a subsystem is removed, the typical or the peak power will be subtracted depending on whether the
server input power budget or the thermal dissipation is to be calculated.
2.2.4. Input Power Budget Allocation
This section explains how to allocate the input power budget for each server. This method can be used
when a PDU is to support a known number of ProLiant DL360 servers. It is important to verify that the
calculated power budget allocation will be sufficient to support the worst-case server configurations that
are to be deployed.
The allocated input power for each server is calculated by multiplying the allocated input current for each
server with the line voltage.
Example
Assume a high voltage PDU rated at 24A is to support 21 servers. Each server can be allocated 1.143A. If
the line voltage is assumed to be at 208V then the allocated input power budget for each server will be
(1.143*208) = 238W.
Since the input power budget of 238W satisfies the fully configured system measured input power of
185W (as shown in Table 2-3), 21 ProLiant DL360 servers may be supported by a 24A high-voltage PDU.
That means, only two of these PDUs are needed to support 42 servers in a 42U rack. This example
configuration is further explained in Section 3.1.
Allocated Input Power = Allocated Input Current * Input Line Voltage