Day 24: Disaster Recovery and Backup

Disaster Recovery Overview: Disaster recovery (DR) is a set of policies, tools, and procedures designed to enable the recovery or continuation of vital technology infrastructure and systems following a natural or human-induced disaster. The goal is to minimize downtime, data loss, and financial impact in the event of a disaster.

Key Metrics:

• Recovery Point Objective (RPO): This is the maximum tolerable period during which data might be lost due to a disaster. It defines the point in time to which systems and data must be restored.
• Recovery Time Objective (RTO): This is the targeted duration of time within which a business process must be restored after a disaster to avoid unacceptable consequences. It measures the time it takes to recover systems and resume normal operations.

Strategies:

1.Backup and Restore:

• Description: Regularly backup data and system configurations, and in the event of a disaster, restore them to the last known good state.
• Pros: Simplicity, cost-effectiveness.
• Cons: Potentially longer recovery times.

2.Pilot Light:

Description: Maintain a minimal version of the infrastructure (a “pilot light”) that can be quickly scaled up in case of a disaster.

• Pros: Faster recovery compared to backup and restore.
• Cons: Higher cost than backup and restore.

3.Warm Standby:

Description: Keep a scaled-down version of the fully functional system running.

• Pros: Faster recovery than pilot light, more resources are pre-allocated.
• Cons: Higher cost than pilot light, but lower than a hot site.

4.Hot Site/Multi-Site Approach:

• Description: Maintain a fully operational duplicate of the infrastructure at a separate location.
• Pros: Minimal downtime, minimal data loss.
• Cons: Highest cost among the strategies.

Backup Strategies:

1.EBS Snapshots (Amazon Elastic Block Store):

• Description: Point-in-time snapshots of EBS volumes, allowing for easy recovery of volumes.
• Use Case: AWS environments.

2.RDS Automated Backups / Snapshots:

• Description: Automated backups of Amazon RDS instances, including database and transaction logs.
• Use Case: AWS RDS managed database environments.

3.Regular Pushes to S3 / S3 IA / Glacier:

• Description: Regularly backing up critical data to Amazon S3 (Simple Storage Service) or its storage classes like S3 IA (Infrequent Access) or Glacier (cold storage).
• Use Case: Storing critical data in AWS.

4.Lifecycle Policy:

• Description: Automate the transition of objects between storage classes or delete them when they are no longer needed.
• Use Case: Cost optimization and data management.

5.Cross-Region Replication:

• Description: Replicate data across different AWS regions for added resilience.
• Use Case: Geographical redundancy and compliance requirements.

6.From On-Premises: Snowball or Storage Gateway:

• Description: Use AWS Snowball for large-scale data transfer or AWS Storage Gateway for seamless on-premises to cloud integration.
• Use Case: Migrating or backing up on-premises data to AWS.