A method for data retention in a data cache and a data storage system are provided. The data storage system (100) includes a storage controller (102) with a cache (103) and a data storage means (106). The cache (103) has a first least recently used list (104) for referencing dirty data which is stored in the cache (103), and a second least recently used list (105) for clean data in the cache (103). Dirty data is destaged from the cache (103) when it reaches the tail of the first least recently used list (104) and clean data is purged from the cache (103) when it reaches the tail of the second least recently used list (105).
