The tape retention in days configuration parameter determines how many days’ backup tapes are protected from being overwritten. The default value of tape retention in days is 0. Which means that backup tapes can be overwritten immediately.
Use sp_configure to change the tape retention in days value. The new value takes effect the next time you restart Adaptive Server:
sp_configure "tape retention in days", 14
Both dump database and dump transaction provide a retaindays option that overrides the tape retention in days value for that dump.
