Data Retention in your Google Security Operations account
By default, Google retains twelve months of your data in your Google Security Operations account. This retention period can be extended as part of your Purchase Order. The retention period applies to all of the data in your Google Security Operations instance. For example, you can't modify the data retention policy for a specific log type.
Google uses an automated system to remove historical data based on event and detection timestamps.
To learn about where data in the Google Security Operations account is stored, see SecOps service locations.
For more information, see Google Security Operations pricing.