Should you monitor at the rack PDU or Busway system tap box level? This is a common question among customers who are looking into rack power monitoring. Today, we’ll give you the low-down.
“Monitoring at the rack PDU level is often considered complementary to tap box monitoring, but it actually turns out that tap box monitoring is not an alternative to monitoring at the PDU level,” explains Ashish Moondra, Sr. Product Manager for Power, Electronics & Software at Chatsworth Products’ (CPI).
Here’s why…
More Granular Monitoring
Monitoring at the tap box level will only provide current and power measurements for the entire PDU, whereas monitoring at the PDU level not only provides information and alerting capabilities for the entire PDU, but also for the branch circuits on the PDU. Branch circuit metering provides information on the amount of current flowing through each breaker on the PDU. This is important because it allows monitoring in situations when the entire PDU may not be overloaded, but when a branch circuit is.
Ideal PUE Information
Measurement at the PDU level is also crucial for Power Usage Effectiveness (PUE) calculations. Information at the PDU levels provides a better indication of the actual power draw for the IT equipment. Losses across the power cord length in between the tap box and the PDU can skew up the total IT equipment power consumption information.
Proper Ownership
In many organizations, busway systems and their tap boxes generally come under the authority of the facilities groups. They may not provide the visibility into cabinet-level power consumption to the IT staff.
Smart Cabinet Integration
Monitored PDUs not only provide electrical measurements, but also have the ability to provide integrated environmental monitoring, as well as integrated cabinet level access control.
Individual IT Equipment Information
A more robust monitoring PDU, such as CPI’s Monitored Pro eConnect® PDU, provides information on power draw for each individual IT equipment. This information helps reduce energy consumption in many ways:
1. It enables power chargeback reports, which brings accountability.
2. It provides the ability to determine ghost servers.
3. It helps to determine the best servers to use in order to keep energy footprint low.
4. It helps to identify which servers are be best suited for consolidation and virtualization.
Outlet Switching Capability
PDUs with switching capabilities—such as eConnect Switched PDUs—provide data center manager with the ability to remotely turn IT equipment on and off. Switched PDUs also provide proper provisioning of outlets inside the rack. This allows data center administrators to keep unused outlets in the off position, or turn them on as needed.