In certain embodiments, the cache management application 116 demotes tracks from the two-tier cache 104 by taking into account the LRU list 118 which is augmented with the minimum retention time for tracks where such minimum retention times are available. An attempt is made by the cache management application 116 to satisfy the minimum retention time requirements to the extent possible, while at the same time preventing the two-tier cache 104 from becoming full.

FIG. 2 illustrates a block diagram 200 that shows demotion of tracks from a LRU list that does not incorporate a minimum retention time for selected tracks, in accordance with certain embodiments.

For simplicity, only four tracks, denoted as track K 202, track C 204, track D 206, and track B 208 are shown in FIG. 2, although a typical LRU list may have thousands or tens of thousands of tracks.

The LRU end of the list is towards the top (as shown via reference numeral 210). As a result, track K 202 is the least recently used track, and track B 208 is the most recently used track.

Unless minimum retention time information was included with the tracks, track K 202 is demoted in a conventional LRU based cache replacement policy (as shown via reference numeral 212). However, if track K 202 is likely to seek entry to the cache shortly after demotion (for example in a situation where a host application 120 indicates that track K 202 should have a minimum retention time), then the cache hit ratio would be decreased.