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Difficulty: HardBackup and Restore Management

A company runs a critical database on Amazon EC2 instances with Amazon EBS volumes in the us-east-1 Region. To meet a low Recovery Time Objective (RTO) during disaster recovery drills, a SysOps Administrator enables Fast Snapshot Restore (FSR) on the EBS snapshots in us-east-1. The EBS snapshots are copied to the us-west-2 Region daily using an AWS Backup plan. During a disaster recovery drill in us-west-2, the administrator restores an EBS volume from the copied snapshot into the us-west-2a Availability Zone. However, the database experiences high initial I/O latency, and the restored volume does not perform at its provisioned limit immediately.

Which of the following is the most likely cause of this performance degradation?

  1. Fast Snapshot Restore (FSR) is not automatically enabled on copied snapshots, and it must be explicitly enabled for the copied snapshot in the destination Region and target Availability Zone.Answer
  2. B
    The copied snapshot in the destination Region must be restored as part of a Multi-AZ deployment to enable automated instant initialization across all Availability Zones.
  3. C
    The source EBS volume did not have versioning enabled, which prevented the Fast Snapshot Restore state from replicating to the destination Region.
  4. D
    The restored EC2 instance and EBS volume were launched in a public subnet that lacks a route to an Internet Gateway in its route table, blocking the volume initialization traffic.

Answer

Fast Snapshot Restore (FSR) is not automatically enabled on copied snapshots, and it must be explicitly enabled for the copied snapshot in the destination Region and target Availability Zone.
The correct answer is that Fast Snapshot Restore (FSR) is not automatically enabled on copied snapshots, and it must be explicitly enabled for the copied snapshot in the destination Region and target Availability Zone. When an EBS snapshot is copied across Regions, it acts as a standard snapshot in the destination Region. FSR must be explicitly enabled on the copied snapshot for the specific Availability Zones where the volumes will be restored. This ensures that the restored EBS volume has its blocks pre-warmed, avoiding the lazy-loading latency associated with pulling block data from Amazon S3 upon first access.

Step-by-Step Solution

1
Analyze the behavior of EBS snapshots restored in a secondary Region.
Recognize that EBS snapshots copied across Regions do not retain their FSR status.
FSR is a property of the snapshot in a specific Region and Availability Zone, and copying the snapshot only copies the block data, not the FSR state.
2
Identify the cause of I/O latency upon volume restoration.
Identify that without FSR enabled on the copied snapshot in the destination Availability Zone, the restored volume must read blocks directly from Amazon S3 (lazy-loading), which causes initial latency.
EBS volumes created from standard snapshots require blocks to be pulled from S3 when first accessed unless FSR is active to pre-initialize the blocks.
3
Determine the required resolution.
FSR must be explicitly enabled on the copied snapshot in us-west-2 for the us-west-2a Availability Zone before restoring the volume.
This pre-initializes the blocks in the destination Availability Zone, ensuring the volume delivers maximum performance immediately upon creation.

Key Concept

EBS Fast Snapshot Restore (FSR) constraints and behavior across Regions and Availability Zones
Estimated Time:2m 30s
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Topics

Backup and Restore Management

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