Record lifetime Option

The SMS gateway option specifies the lifetime in seconds of a historical record. Records older than this lifetime will be purged from memory; history files older than this lifetime will be deleted from disk. By default, a value of 259,200 seconds (3 days) is used. Records stored in memory are purged in sweeps by a thread dedicated to managing the in-memory data. These sweeps occur every  seconds. Files on disk are purged when it becomes necessary to open a new history file.

The default value is: 259200

See also:
 * history_file_rollover_period Option
 * SMS gateway options