ServerTech Blog - Information for the Data Center Equipment Manager

Cabinet-level Power Distribution Unit (CDU) outlet control

Switchable outlets are not a new feature for CDUs however the debate on whether or not outlets should be switched is ongoing. Server Technology has Switched CDUs which offer individual and group based switching outlets, Sentry Power Manager adds outlet clusters, outlets that span CDU, span cabinets or span datacenters.

Have you had the need to reboot or power-cycle a server? Yes, I know that is an old topic to bring up again, considering the high adoption rate of virtual systems but is the need still there?

Switchable outlets are a powerful feature when used properly. Did you know that with local role-based access control (RBAC) that a user on a switched CDU can have the switchable feature disabled? While on the topic, did you know that Switched CDUs, Smart CDUs too, support not only RBAC but LDAP (AD), TACACS+ and RADIUS? With the support of a variety of different authentication protocols, the CDUs give you the ability to give as much or little privileges depending on the duties of the user.  

We would like to hear from you! What are your thoughts on switchable outlets? Do you love them? Do you not? From those who think that they should just ‘be friends’ with switched outlets we’d like to hear from you? For those who got a holiday present for their switched outlets we would also like to hear from you!!!

Sentry Power Manager Data Integration

Did you know that Sentry Power Manager (SPM) has a web services API that supports both SOAP and REST? By being able to make use of the polled data from Sentry Power Manager’s database, what would you do with it? Who would you share it with? What systems, that you currently have, would benefit from the data sharing?

One of the features of SPM is its capability to allow the user to turn data, polled, into usable business information. But what does that mean? Can a static report be usable information? Can the same be done with a trend? In my opinion the answer is yes, I think that reports, either static or over a period of time, will give extra insight as to the consumption of energy and environmental data.

Canned reports within SPM are very powerful but when a user needs more, the SOAP/REST interface will allow the data from SPM to be shared and presented to a wide variety of DCIM, NMS and BMS packages.

Please contact us for more information about the interface to these export protocols.

PUE and SPM

Sentry Power Manager (SPM) has a Power Usage Effectiveness (PUE) report built into the system. PUE is the ratio of the total amount of power used by a Data Center to the power delivered to the computing equipment. The PUE report requires that the value for the Total Facility Power for the Data Center (Location) be input into the Setup page of the Location.

In order for the PUE report to be valid, it is imperative for all of the IT load numbers to be represented in the power consumption reports. A typical Data Center can be divided into three sections: the server cabinet section, storage section and network section. For each of the divisions there are different types of PDUs available for power measurements.

For the server cabinet section there is a wide variety of vertical and horizontal CDUs ranging from 2 outlets to 84 outlets. For the storage section there is the Sentry Smart Power Monitor, I like to refer to this PDU as the two in/two out unit… basically it is an inline power monitoring unit for cabinets that have basic or metered PDUs in them. Finally there is the network section and the CS-4 and CS-6 PDUs allow for a large input feed and either 4 or 6 NEMA locking outlets.This PDU not only allows for the monitoring of the larger outputs but also helps combat the issue of stranded energy.

When used together the PDUs listed above will be able to give the user a much larger, more encompassing view of the power consumed through a higher percentage of the IT load when compared to solely viewing the power consumption of the server cabinets. These combined readings will help make sure that everything is included within the PUE report.

Circuits, lines and groups… oh, my!

Per-Outlet Power Sensing (POPS) cabinet PDUs are really an invaluable resource within a Data Center for many types of administrators. They offer a very finite level of measurement and can offer more insight into power consumption than what has previously been available.

The low level monitoring is important and the aggregate information that can be surmised by those readings is gaining in value every day.

A facilities manager knows the total of power consumed in the data center. A data center manager can understand what a specific device consumes from an energy point of view. A UPS can show someone a power number for a large number of devices or an area of the data center. Now there is a new way to report on these criteria from Sentry Power Manager. Aggregates of POPS or branches of a cabinet PDU can be put together to build reports of groups of outlets, groups of infeeds, server cabinets and groups of server cabinets.

By being able to build these new cross sections, it eliminates the guess work and allows for metering of different levels of consumption. What I like about this is that even though some of these readings are currently available today, they can be had by looking at more than one system. For the record I am not saying or inferring that is a bad thing. The benefit is that now more people can have more vantage into the inner workings of a Data Center.

This just in, custom reports…

Server Technology cabinet PDUs have the ability to measure and share power and environmental information. The GUI embedded on the CDU firmware allows users to see the readings. Sentry Power Manager has at least 40 canned reports built into the system. These reports are useful to help solve many business and technical related issues within the server cabinet and in the data center. The easy-to-create and simple-to-read reports can be used by SPM users as well as they can be  shared with other systems through Microsoft Excel, Word and XML output. The system can also be queried by SNMP polling systems, NMS, BMS, DCIM systems via SNMP and web services (SOAP/REST).

Custom reports can be created via different output dumps. Server Technology is continually improving the Sentry Power Manager system by working with existing users and talking with new users and/or prospects. It is our goal to take the voice of the customer and use it to shape all of our products into products people are proud to own versus products people are forced to use.

 

What do you monitor within the server cabinet?

When considering power, temperature and humidity within a server cabinet, what do you measure? Where do you measure? How often do you measure? What do you do with the measurements? Who, within your organization, uses the measurements?

There are many thoughts and opinions on what and where to monitor power and environmental information and the cabinet PDU can be the monitoring point. I think the questions on who, what, where and when will continue to be a topic of discussion… the one thing that is certain is that the cabinet PDU offers the monitoring capabilities that Data Center Managers are in need of.

 

By Marc Eisenberg, Senior Systems Engineer

What is Smart Load Shedding?

Server Technology offers a product which will allow a Switched cabinet power distribution unit (PDU) to react to certain thresholds, such as temperature, load and UPS status. The blog entry is more of a poll than anything… who out there would allow a CDU to react to temperature, power or status parameters?

Would you feel comfortable allowing a cabinet PDU react automatically to a possible damaging situation?
Out of the three parameters which would you most likely use?

Temperature  -  should supplemental cooling be lost or airflow disturbed and temperature within a server cabinet get too high, would there be a benefit to turning off the outlets of a cabinet PDU to protect the IT devices from an over-temperature scenario?
In-feed load - can load shedding help support capacity management and redundancy?
UPS status - should a UPS go from utility power to battery power, would there be a benefit to
  turn off IT devices that had a lower importance than others to maximize the battery
  power?

Since this more of a poll versus a traditional blog, I have one more question… Would you be more interested in Load Shedding versus Load Loading, meaning turning outlets/devices on after an event?

 

By Marc Eisenberg, Senior Systems Engineer

What do a hurricane and a Data Center have in common?

Aside from air movement, I am hoping not too much. The storm that hit the Atlantic seacoast in late August caused a lot of things from evacuation s to flooding and much more. Data Center managers braced for the worst prior to the arrival of the storm.

How can Sentry Power Manager help you prepare for a hurricane? For starters it can help by assuring preparedness and from another vantage it can help by being able to react from a remote location. In a time of emergency clear, concise messaging is key. Sentry Power Manager gives users the abilities to set thresholds from power consumption to temperature to water sensing. Should an issue arise and immediate attention be require, the remote capabilities of Sentry Power Manager can allow an administrator to control a cabinet power distribution unit (PDU) in an effort to protect or regain control of connected equipment.

By Marc Eisenberg, Senior Systems Engineer

Datacenter rack based power strip outlet power state status indicator question

 Salaam: I had a situation where another vendor’s networkable power strip gave me an incorrect indication of an outlets power state, the LED indicated an ‘On’ status and no power was available at the outlet.  Can this happen on a Server Technology power strip with outlet control? 

Reply:    This condition should never be possible due to how the outlet state Light Emitting Diode (LED) indicator is wired and controlled on the Server Technology Switched Cabinet Power Distribution Unit (CDU).  The outlet state LED indicator on the Server Technology Switched CDU is controlled by the potential (Voltage) at the outlet itself, as opposed to allowing the controller to directly control the LED based on the controllers perceived outlet status.  Therefore, the controller interface module provides the ability to control the outlet state (turn the outlet on, off & reboot), and the actual outlet state controls the LED indicator.

It should be noted that the resulting answer really has to do with the care taken in a specific engineering design methodology and how a LED semiconductor functions to produce visible light (photons).  The design implementation details can and will affect the functional implications along with the probability of undesirable results - vendors designs are not always equal.

Ask the Engineer

Can a cabinet/rack based power distribution unit with a higher Ampere rating be used with a lower ampere rated power feed?

For example, can I connect a 50A rated cabinet power distribution unit to a 30A whip:

Using a 50A CDU on a 30A circuit is acceptable.  The circuit itself MUST be limited to 30A maximum by the primary upstream Over-Current Protective Device (OCPD).  Usage of the CDU in this manner would require an adapter with the appropriate connector for the 50A rated CDU to connect with the 30A rated power feed (30A male plug on one end and a 50A female receptacle on the other). 

With the selection of any vendor’s cabinet/rack CDU/PDU you should be sure the CDU/PDU provides compliant branch circuit protection, and the source itself MUST always be limited by the primary upstream OCPD to the lowest common denominator with respect to ampacity throughout the entire chain. 

What are the primary causes of a tripped circuit?

In not so technical terms a tripped circuit is caused by:  too much stuff connected to it, an under-provisioned circuit or unexpected power draw.  In some cases, an available outlet means available power, but the theory of checks and balances doesn’t always mean that even though there is an available outlet, that there is available power. 

Another main cause of a tripped circuit is not understanding actual consumption at the cabinet level.  With branch circuit monitoring we have a good idea of what is being consumed on the branch as a whole but what is missing is the breakdown of consumption downstream on the branch - at the cabinet level. 

By Marc Eisenberg, Enterprise Systems Manager