When an application program requests new data and the cache is full, the Cache Manager discards some data to make room for the new information. It discards data based on the following two factors:
· If the data is reproducible; information is considered reproducible if it is unchanged from its first retrieval. By definition, data from read-only filesets is always reproducible; data from read/write filesets that was changed by a local application is considered reproducible if the changes are stored to the File Server machine.
· When the application program last referenced the data; data not used for the longest time is discarded first.
Thus, reproducible data not used for the longest time is discarded first. The Cache Manager continues to discard least-recently used (LRU) data in this fashion until there is enough room for the new data.
You can force the Cache Manager to discard, or flush, data cached from files, directories, and filesets. You can flush individual files or directories with the cm flush command, or you can flush one or more filesets with the cm flushfileset command. Flushing is necessary only in the event of file system problems or for testing purposes. The cm flush and cm flushfileset commands do not cause the Cache Manager to discard changes to data not written back to the central copies of files. These commands also do not affect data in the buffers of application programs.
The Cache Manager checks once an hour for changes that do not involve tokens, such as the release of a new version of a cached read-only fileset or a name change for any cached fileset. You can force the Cache Manager to notice these changes at other times with the cm checkfilesets command, which directs the Cache Manager to revise its table of mappings between fileset names and fileset ID numbers.
More:
Flushing Specific Files or Directories
Flushing All Data from Specific Filesets
Forcing the Cache Manager to Notice Other Fileset Changes