For example, by including computed check bits, ECC memory is capable of detecting and correcting single-bit errors within each memory word, while RAID 1 combines two hard disk drives (HDDs) into a logical storage unit that allows stored data to survive a complete failure of one drive.
[3] While different in nature, data redundancy also occurs in database systems that have values repeated unnecessarily in one or more records or fields, within a table, or where the field is replicated/repeated in two or more tables.
Often this is found in unnormalized database designs and results in the complication of database management, introducing the risk of corrupting the data, and increasing the required amount of storage.
For instance, when customer data are duplicated and attached with each product bought, then redundancy of data is a known source of inconsistency since a given customer might appear with different values for one or more of their attributes.
[4] Data redundancy leads to data anomalies and corruption and generally should be avoided by design;[5] applying database normalization prevents redundancy and makes the best possible usage of storage.