MTBF
also: MTBF, Mean Time Between Failures
Mean Time Between Failures (MTBF) is a statistical measure of how long, on average, a hardware component or system operates before experiencing a failure. It's expressed in hours and used to estimate reliability and plan maintenance.
MTBF is calculated from historical failure data and represents the expected operating time between breakdowns. For example, a hard drive with an MTBF of 100,000 hours means that, statistically, you can expect it to fail after roughly 100,000 hours of continuous operation—though individual units may fail sooner or last longer.
MTBF is commonly used when comparing hardware reliability, especially for data center components like servers, drives, and power supplies. A higher MTBF indicates greater reliability. However, MTBF does not predict when a specific device will fail; it's an average across many units under normal operating conditions.
Related to MTBF is MTTR (Mean Time To Repair), which measures how long repairs typically take. Together, these metrics help organizations plan redundancy, backup strategies, and maintenance windows to minimize downtime.