Data retention refers to the policies governing the management of data. A data retention policy consists of rules that determine the duration for which data should be stored, when it should be deleted, and the circumstances under which it should be retained or archived.
It helps answer questions such as "How long should the team retain the data?", "What storage or archival mechanism is used for the data?", and "Where should the data be stored?"
Data retention makes sure you do not incur significant costs in maintaining large amounts of data in your hot database which is expensive. Instead, moving older data into a colder database (which is much cheaper) which is not needed for fast retrieval in your application saves that cost and reduces maintenance needed for the database size.
What’s the difference between Data backup and Data archival?
Data backup involves duplicating or creating a copy of the original data and storing it in another location. This is done as part of a contingency plan to prevent data loss. On the other hand, data archival focuses on making inactive data that is no longer needed for the organization. The reasons for data archival are typically legal or compliance-related.
Read more about the data retention policy here - https://www.techtarget.com/searchdatabackup/definition/data-retention-policy