Data Durability

Data durability is a measure of how resilient your data is against loss within a certain period. It can be used to measure the reliability of a storage system. It is only a measure of how likely you are to lose data. It does not measure how much data might be lost. Data durability is estimated for a one-year period.

The main factors that affect data durability are the number of redundant copies, disk failure rate, and how long it takes to recover data. Each additional copy can increase data durability by 99% to 99.9%. Cloud object storage typically uses three copies to provide 11 to 12 nines of data durability.