DAYS_TO_KEEP_LOGS entry in vm.conf
If this entry is specified in vm.conf, specify the number of days to keep debug logs before vmd deletes them. This entry is read and interpreted on the hosts where vmd is running.
DAYS_TO_KEEP_LOGS = days
The default is 30 days. A value of zero means that the logs are not deleted. This entry does not affect the debug logs that Unified Logging creates.
Information about Unified Logging is available in the NetBackup Logging Reference Guide.