MTTR

MTTR stands for Mean Time To Repair.
MTTR is the amount of time between when something breaks and when it has been repaired and is fully functional again.
If an Ethernet card in your workstation breaks and it takes 3 hours to purchase and install a new card, the MTTR for the workstation is three hours. The ethernet card is still broken, and probably will never be repaired. The MTTR for the ethernet card is forever.
MTTR includes:
• Time spent troubleshooting the error
• Time spent resolving the error
• Time spent waiting for the error to be resolved
MTTR represents the amount of time that the device was unable to provide service.
MTTR numbers are calculated for each component and service. If a redundant server fails, that server may have a MTTR of two days, but the service will not be interrupted and will therefore not have an MTTR.
Reducing MTTR
Reducing MTTR for a system can be an important step in improving uptime and service levels.
Troubleshooting time can be greatly reduced by steps such as:
• Documenting systems
• Implementing change mangement
• Documenting standard operating procedures
Time spent waiting can be reduced by methods such as:
• Keeping equipment spares on-hand
• Negotiating sparing agreements with equipment vendors
• Maintaining an accurate on-call list for critical maintenance personnel