Two variables are needed to determine the how much data is stored and for how long:

1. RETAIN_NUM_MONTHS This environment variable controls the vacuum processes and determines how much data is stored in the database.  Example: 5 → Keeps up to 5 months of data; older data is purged
2. INITIAL_INGEST_NUM_MONTHS: Controls how much data is allowed to be processed during initial process. Example: 2 → New providers will only ingest the last 2 months of data (not 5)
3. INGEST_OVERRIDE: seems to be required as well for INITIAL_INGEST_NUM_MONTHS to take effect

The env-vars should be added to the masu deployment, also RETAIN_NUM_MONTHS is needed by koku-api.

Verify with koku project and follow defaults:

https://github.com/project-koku/koku/blob/3d6aa5dca1094d21af0f18697958d6f5b75f2873/koku/masu/processor/orchestrator.py#L194

https://github.com/project-koku/koku/blob/3d6aa5dca1094d21af0f18697958d6f5b75f2873/koku/masu/processor/expired_data_remover.py#L52