How Reliable Is Your Infrastructure?

Fri, 09/24/2010 - 9:42am

As organizations become increasingly dependent on data center systems, there is a need for greater reliability in the critical infrastructure – and the reliability of a system only lasts as long as the shortest component life in the unit.

What is Preventive Maintenance?

Preventive maintenance is used to ensure maximum reliability of data center equipment by providing systematic inspections, detection and correction of incipient failures, either before they occur or before they develop into major defects that result in costly downtime. Preventive maintenance can include activities such as inspections, tests, measurements, adjustments, parts replacement, and general housekeeping practices.

Why is Preventive Maintenance Important?

As organizations become increasingly dependent on data center systems, there is a need for greater reliability in the critical infrastructure – and the reliability of a system only lasts as long as the shortest component life in the unit. Preventive maintenance is critical for minimizing unit-related failures, maintaining system cooling efficiencies, and managing operating costs.

What is the Return on Investment of Preventive Maintenance?

The number of preventive maintenance visits in a data center has a substantial impact on system reliability and less downtime – and that translates into direct savings for data center managers.

The return on investment for preventive maintenance can be observed by calculating the Mean Time Between Failure (MTBF). MTBF is an industry recognized measure of availability that uses the number and types of failures that products actually experience in real applications.

In general, a higher MTBF number, stated in hours, indicates a more available unit. For example, a UPS unit with an MTBF of 2 million hours is more available than a unit with an MTBF of 1 million hours.

Regular preventive maintenance increases the MTBF. For example, the MTBF for a system that receives one annual preventive maintenance visit is ten times greater than a system that receives zero preventive maintenance visits. By contrast, a system that receives four annual preventive maintenance visits, as opposed to zero visits, increases its duration between failures by 51 times.

Two key statistics are incorporated into MTBF; cumulative operating hours and number of unit-related failures, to calculate average availability across all units in a given population.

The formula is as follows:

MTFB =cumulative operating hours/ number of outages + 1

Preventive Maintenance and Power

For many organizations, the IT infrastructure has evolved into an interdependent business-critical network that includes data, applications, storage, servers and networking. A power failure at any point along the network can impact the entire operation – and have serious consequences for the business.

To keep running through power outages, utility spikes and other unforeseeable power issues, critical systems are dependent on the reliability of the Uninterruptible Power Supply (UPS) systems.

UPS systems are designed to offer the utmost reliability and performance, but in reality, failures still occur. Data center managers who are proactive with preventive maintenance will greatly reduce their chances of downtime.

Preventive maintenance programs maximize the reliability and performance of the UPS systems by providing systematic inspections, detection and correction of incipient failures.

How Often is Preventive Maintenance for Power Needed?

The frequency of preventive maintenance depends on the type of UPS. Small UPS devices should be inspected annually, but medium and large systems should be inspected at least twice a year, sometimes more. Below is a checklist for semi-annual and annual preventive maintenance service.

Batteries are Important to Your UPS

Batteries are an important element to a data center’s UPS – and unfortunately, they’re often overlooked. Semi-annual and annual preventive maintenance will typically include the inspection of batteries, but it is recommended that data center managers also implement a preventive maintenance program specifically for batteries in their system. Stay tuned for more information on batteries and battery monitoring in our next chapter.

Preventive Maintenance and Cooling

Preventive maintenance is also critical for maintaining system cooling efficiencies, operating costs, and minimizing potential downtime. Cooling modules have moving parts that eventually wear out. Preventive maintenance ensures that these components last as long as possible. It also ensures these components perform within their originally designed operating parameters, allowing data center managers the opportunity to replace components before they fail.

How Often is Preventive Maintenance for Cooling Needed?

Like preventive maintenance for UPS systems, the frequency and task for cooling preventive maintenance can vary depending on the model. The factory recommends at least four preventive maintenance visits per year, replacing belts and filters as necessary (typically two times per year for filters and one time per year for belts).

When to Get a Professional Involved

Most preventive maintenance measures should be left to a qualified and trained professional. UPS and batteries contain high voltage, and only qualified personnel should attempt preventive maintenance or repair. Data center managers can and should provide preventive support by replacing air filters when dirty, ensuring environmental specifications are met and maintained, and monitoring the UPS for alarms.


In the current economic environment, many organizations are relying heavily on existing equipment to maintain operations, making preventive maintenance more important than ever before. Preventive maintenance is a critical component of every data center, and it should not be overlooked. Without it, data center managers are compromising the efficiency, optimization and availability in their facilities.

Liebert Services is committed to helping organizations understand their critical infrastructure, identify problems, and incorporate solutions. For more information, visit


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