Assuming it is the same in 5.7.2 as in 5.7.1:
in your conf/analytics/advanced.properties file
#Old Data Cleaner Execution frequency. Default is 0(Off) days
oldDataCleanerExecutionFrequency=7
#old date range for FSDB. Default is 180 days
oldDataCleanerDateRange=210
#amount of disk to be freed in percentage
diskSpaceFreeupPct=10
noOfDaysForDiskSpaceAverage=7
# old data cleaner range for alerts and alarms
oldAlertsCleanerDateRange=90
Note: in 5.7.1, and I'm guessing it is not fixed in 5.7.2, the old data cleanup does not keep the data for 180 days; if you want 6 months, you need to use 210. Data is stored by month in the FSDB and instead of deleting everything prior to 180 days ago, for example, if today minus 180 was May 2, it would delete May. Which only leaves 5 months.
If you also want to automatically delete resources which are "not existing", in your user/conf/controller/controller.properties file, set the following:
#automatically delete not existing resources
deleteNotExisting = true
#time in hours an object must be in the not existing state before it can be deleted
deletionPeriodInHours=720
#time in hours between resource deletion scheduling
deletionSchedulePeriod = 24
