Data center reliability essentially refers to the ability of the facility to perform its functions optimally under specific conditions for a stipulated time period. Availability refers to the extent to which a data center facility or system can be operational and also accessible whenever needed. So, reliability will obviously also influence availability. In any data center, reliability is of crucial importance because whenever there is a failure, the biggest concern is getting the hardware and functions running normally as soon as possible so as to guarantee the lowest possible downtime for any business.
When speaking of reliability, the mention of the 59s is very common and this refers to 99.999% up-time which is the highest measure of reliability for a data center. However, it is really used to denote the time for which the data center had been powered up. Power loss is only one factor which can affect availability. Every time the server faces a power outage, it will need to reboot and restore data. This time taken for data recovery could stretch into days in some situations. Other important factors which can well affect availability are the lack of cooling systems and this may lead to down-times when equipment's get overheated. There may also be threats in the form of exposure to temperature extremes, high humidity, component malfunctions and outdated components. Finally, there may well be tornadoes and floods and other calamities which can pose huge threats to reliability and availability.
So, when you choose a data center, it must be ideally of the Tier III category which is powered by dual power supplies. This will improve server stability and reliability. The Tier III facilities are most fault-resilient and therefore less likely to collapse. They are supported by compartmentalized security zones which have bio-metric access controls. There will be armed guards for surveillance of the premises and man traps at the entrance. There will also be CCTV cameras for additional surveillance and visitor access restrictions through ID checks.