Data Retention Policies: Balance Compliance and Cost

Data Retention Policies: Balance Compliance and Cost

Align data retention periods with actual business and compliance requirements to avoid paying for unnecessary historical data storage.

Understanding Retention Costs

Every day of retention adds to storage costs. Organizations often keep data "just in case" without considering the financial impact.

Retention Policy Framework

By Data Type

• Transactional data: 7 years (compliance)
• Analytics/aggregated: 1-2 years
• Logs/events: 30-90 days
• Staging/temp: 1-7 days
• Development: 1-3 days

Implementation

-- Set retention at database level
ALTER DATABASE analytics
SET DATA_RETENTION_TIME_IN_DAYS = 7;

-- Override for specific tables
ALTER TABLE financial_transactions
SET DATA_RETENTION_TIME_IN_DAYS = 90;

-- Minimal retention for staging
ALTER TABLE staging_data
SET DATA_RETENTION_TIME_IN_DAYS = 1;

Archival vs Deletion

-- Archive before deleting (for potential future access)
COPY INTO @archive/old_data/
FROM (SELECT * FROM production WHERE date < '2022-01-01');

-- Then delete from production
DELETE FROM production WHERE date < '2022-01-01';

Best Practices

1. Document retention requirements by data type
2. Align with compliance and legal requirements
3. Use transient tables for non-critical data
4. Archive before deleting valuable data
5. Review retention policies quarterly

Real-World Example

A company kept default 90-day retention on all 200 tables. After audit: 150 tables only needed 1-7 days, 30 tables needed 30 days, 20 tables needed 90 days (compliance). Storage reduction: 45TB to 18TB. Savings: $6,480/month (64% reduction).

Key Takeaways

• Default retention settings often exceed actual needs
• Set retention based on data type and compliance requirements
• Use transient tables for staging and temporary data
• Archive valuable data before deletion
• Regular policy reviews identify optimization opportunities