Air flow
Proper airflow can do more than anything else to reduce temperatures around critical hardware. If the equipment is installed too dense, or if the server room or data center is cluttered, air will be unable to freely circulate. Fans and cooling equipment will be of little use if cooler air cannot get through to replace warmer air. Make sure you have sufficient airflow around critical equipment.
Physical checks
Physically check the system airflow and fan operation in your data system. Sensors and monitoring systems can fail. Heat can cause fans and hardware to fail. If at all possible, personnel should physically verify air circulation and fan operation. Routinely maintain airflow by removing dust and lint via compressed air or vacuum.
For remote locations, it may be impossible to physically verify airflow or fan operation. In such cases, installing lights-out monitoring for critical systems may be the only choice.
Saving money can cost you
Whether the emphasis is on being green or just saving money, more and more operations are turning off the air conditioning on the weekends. While this may be an environmentally friendly cost-cutting measure in some cases, data centers and server rooms are not the places to implement this policy. The resulting heat build-up poses a severe risk to data processing hardware.
The costs associated with server failure may far outweigh the energy cost savings. Serious consideration of the risks involved should be given before implementing any policy involving shutting off the air conditioning for any amount of time. If the rest of the building must be shut down, it may be cost-effective to adjust or install air conditioning specifically for the data center or server rooms.