I have enabled Azure Security Center a year ago. After one year, the Storage account that is collecting Security Center data is 1.5 terabytes in size and costs are starting to add up.
Is there a way to clear out old security data?
Is there a way to limit security/audit data to a certain period of time like 2 months?
You can decide which types of raw data will be collected through Azure Security Center -> Security policy -> your_subscription_name -> Edit settings -> Data collection -> Windows security events. The different choices for data collection are described in the docs.
To configure a retention policy, go to your Log Analytics workspace -> Usage and estimated costs -> Data volume management -> Data Retention.
On deleting old data from Log Analytics, I found this answer on Azure forums (Jul 2018):