File heat is a relative attribute of files/objects which reflects the access frequency of the files/objects. The file heat can be controlled by two system-level constants, time period and loss percentage. Time is divided into time periods. The access number during each time period is counted. But the file heat is only recalculated at the end of a time period. And at the end of each time period, a percentage of the former file heat is lost according to the loss percentage.
File heat mainly designed for cache management. Cache like PCC could use file heat to determine which files to removed from the cache or which files to fetch into cache.
New Feature
Minor
