Labor and Power Savings

By Cameron Sturdevant  |  Posted 2008-10-22

Dominion PX Harnesses Data Center Power

The Raritan Dominion PX is a 1U power distribution unit that provides control over individual outlets to measure power utilization and enable remote reboot. The Dominion PX is a good device for gaining an understanding of real-time power usage in the data center while extending labor-cost-saving control to rack-mounted equipment. 

It looks like a big power strip, but the Dominion PX can play an essential role in helping IT managers get a grip on energy costs; the resulting data center changes could demonstrate cost cuts of 10 percent to 20 percent on recurring energy bills.

Click here for a closer look at the Dominion PX.  

To gain full advantage of the Dominion PX's remote shutdown/restart capabilities, IT managers would have to install the device wholesale throughout the data center. That said, using the device in even a limited way will support a green energy reduction plan.

In addition, using optional, easy-to-install sensors, the Dominion PX can provide remote temperature and humidity data to round out knowledge of the data center operating environment.

Device Security

I tested the Raritan Dominion PX DPCR8-15, a 1U (1.75-inch) form factor, 120VAC, 15-amp, 8x NEMA 5-15R outlet unit that costs $649. The device competes with the APC Cyclades Alterpath ATP0601.

With great power comes great responsibility, and that is true with the Raritan Dominion PX, which started shipping earlier this year and works with Raritan's CommandCenter Secure Gateway.

The Dominion PX's embedded operating system is inaccessible from the outside, and the power management system uses 256-bit AES (Advanced Encryption Standard) to secure command and control data between the management interface and the device itself. The product also supports the use of strong passwords.

During tests, the Dominion PX integrated with my Windows Active Directory infrastructure to ease user management while enabling me to keep a close watch on who was authorized to access the power management features. I was especially happy with the granular control afforded by the outlet-level permissions I established for various users and groups of users.

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I created several groups inside the Dominion PX administration system, and I could tightly define access and control for each. For example, I created a network group that could access only the outlets that powered the switches and routers in the network. The systems group, meanwhile, was allowed to view only real-time power usage and remotely contol those outlets used by servers. The electrician group was the "god operator," with full control over the switch, while the security group was able to see all power activity on the Dominion PX but wasn't able to power cycle the outlets.

I have to admit that I had a fair amount of trepidation when I first installed the Dominion PX because of this extensive remote power cycle ability. And IT managers with any doubts about the strength of their internal security systems--including certificate management-should pause before considering a smart PDU (power distribution unit) implementation. This has nothing to do with any weakness of the Dominion PX or other comparable systems; rather, it has everything to do with ensuring that the underlying network security infrastructure is in place to accommodate such systems.

Labor and Power Savings

The main reason to use an intelligent PDU is to measure and monitor power usage. And the main function of these devices, including the Dominion PX, is to provide alerts when a system begins to use power above an allotted threshold. Such events can be warning signs of overutilization or an electrical or mechanical failure in the monitored resource.

I was able to easily monitor my server systems and network switches that support my VMware ESX cluster using the Dominion PX Web-based interface. I could set minimum and maximum power utilization thresholds, and the Dominion PX uses industry-standard SNMP traps to send alert conditions. This made it easy to integrate the data into existing management tools.

I also used the temperature and humidity probes to monitor my rack-mounted computing resources. The temperature probes are the size and shape of a USB drive. I used zip ties to secure the probes in the air-flow intake and exhaust at several levels of the rack. Using the data supplied by the probes, it was easy to see the real-time air temperature and relative humidity surrounding the equipment. Again, the Dominion PX allowed me to set minimum and maximum thresholds for measurements reported by the probes.

Check out this video of 10 steps to a greener office.

Another good use of the Dominion PX is in remote locations where IT staffers are not routinely present. Using the GUI and when logged in as a user with sufficient privilege, I was able to select individual outlets and cycle the power, forcing a reboot of the device connected to that outlet. This is especially cost-effective in situations where a hard reset would require a truck roll.

The Dominion PX answered a question that had been floating around eWEEK Labs for a while: Just how much power load are we placing on the circuits running our equipment?

Much of our equipment is only lightly loaded for much of its uptime. The Dominion PX let me know that three IBM e325 servers and a 1TB Dell disk array drew 7.9 amps of 120-volt power from a 20-amp circuit when idling. Of course, the voltage for these devices varied widely, and the Dominion PX displayed that data as well.

Using the Dominion PX, I was able to move away from relying on the circuit breaker to get an idea of the electric power needs of my test systems. This would be especially useful information for IT managers for capacity planning. And having more precise power utilization records should help IT managers apportion utility costs when charging back operational costs to business units.

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