📖 What is Amazon EBS Snapshots?
Amazon EBS Snapshots are incremental backups of EBS volumes, stored in S3. They provide point-in-time recovery and disaster recovery capabilities. Snapshots are volume-level and can be shared between AWS accounts or regions.
"Snapshots are *incremental*, reducing storage costs and backup times. They are crash-consistent by default; application-consistent snapshots require application quiescing. Understand the impact of encryption on snapshot sharing and restoration."
📚 Certification: AWS Certified Solutions Architect - Associate (SAA-C03)
🔑 What are the Key Concepts of Amazon EBS Snapshots?
- ▸ Snapshots are incremental, meaning only changed data is saved after the initial snapshot, reducing storage costs and backup times significantly.
- ▸ They are stored in Amazon S3, providing high durability and availability, and are automatically encrypted if the EBS volume is encrypted.
- ▸ Snapshots are crash-consistent by default, requiring application-level quiescing for application-consistent backups to ensure data integrity.
- ▸ Snapshots can be copied to different AWS Regions for disaster recovery or compliance purposes, but copying incurs data transfer costs.
- ▸ Sharing snapshots between AWS accounts is possible, enabling collaboration and simplifying backup/recovery processes, but requires careful IAM permissions.
🎯 How does Amazon EBS Snapshots appear on the SAA-C03 Exam?
You may be asked to identify the most cost-effective method for regularly backing up a critical database EBS volume, considering storage costs and recovery time objectives.
A scenario might describe a requirement for a disaster recovery plan involving replicating EBS volumes to another region – determine the best way to achieve this using snapshots.
Expect questions about how EBS snapshots interact with encryption, specifically regarding permissions needed to restore an encrypted snapshot in a different account.
❓ Frequently Asked Questions
What is the difference between a snapshot and an AMI?
An AMI includes the OS, applications, and data, creating a bootable image. A snapshot is a block-level backup of an EBS volume, requiring an AMI to be bootable. AMIs *use* snapshots.
How can I ensure application consistency in my snapshots?
For application consistency, you must quiesce the application before taking the snapshot. This means pausing writes to ensure data is flushed to disk, preventing corruption during recovery.
If my EBS volume is encrypted, what happens when I share a snapshot?
The recipient account must have permissions to access the KMS key used to encrypt the volume. Without access to the key, they cannot restore the snapshot, even with snapshot permissions.