Each MSS file has a retention period that specifies how many days it should be kept after the time the file is last referenced (by a read, write or metadata update). The retention period ranges from 1 to 32,767 days, and the default is 32 days. If the MSS file is not referenced within its retention period, it is purged from the MSS (see Chapter 5, MSS File Life Cycles for further details). The retention period may be set by msrcp(1NCAR) when writing the file or changed by msretention(1NCAR) later.