What Is Mttr And How Does It Affect You?

By Author: John Cicero
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MTTR, or Mean Time to Repair, is the typical time that a certain device will take to recover from any breakdown. It is the typical time essential to carry out corrective maintenance on all of the removable items in a product or system.

MTTR is a universal measure of reliability. This kind of reliability prediction will give us an approximate measure of how long repairs and maintenance tasks will take in the event of a system failure. An example of such a device is self-reset fuses, where the MTTR would be a few seconds.

MTTR is an important factor in reliability analyses and predictions. MTTR can be used in reliability predictions with regard to electronics and computer systems to approximately calculate the uptime of the system. Uptime is the probability that an item is in a functioning condition at any time, and is based on studying both the MTBF and MTTR.

The MTTR is usually a part of a maintenance contract, where it would cost more for a system whose MTTR was 24 hours, than for one of, say, 7 days.

This, however, does not mean that the manufacturer is guaranteeing that the system would be up ...
... and running again properly by 24 hours of being reported. However, it does mean that the typical repair time will be around 24 hours.
Note: In contracts, some suppliers will interpret MTTR as 'mean time to respond' while others will take it as 'mean time to replace/repair/recover/resolve'. The former means that the supplier will recognize a problem and initiate mitigation within the specified timeframe. Some systems may have an MTTR of zero, which means that they have emergency apparatus which can take over the system instantly.