Amazon RDS now provides visibility into storage volume initialization status
Amazon RDS now provides visibility into the initialization status of database storage volumes created from snapshots. You can use this status to determine when your storage is fully initialized after a restore and is ready to support latency-sensitive database workloads at fully provisioned performance.
When you restore a database instance to a point-in-time, or create a read replica creation, or convert from Single-AZ to Multi-AZ conversion, Amazon RDS creates storage volumes from a snapshot. These volumes undergo initialization, during which storage blocks are downloaded from Amazon S3 and written to the volume before they can be accessed. The initialization rate varies depending on the workload and which blocks are accessed and during this period you may notice increased I/O latency. Previously, Amazon RDS reported the instance as available throughout initialization, giving you no direct signal for when performance would stabilize. The new StorageOperationStatus and StorageOperationPercentProgress fields on the RDS Console and DescribeDBInstances API let you monitor your storage initialization progress in real time, so you can validate when all blocks have been written. You can use the information to time your workloads to align with its completion. The fields also report storage optimization progress so you can plan for full provisioned performance after a storage modification.
Storage volume initialization status is accessible by default for all Amazon RDS database instances in all commercial AWS Regions and US GovCloud Regions. You can start using it today through the Amazon RDS Management Console, the AWS Command Line Interface (CLI), or the AWS SDKs. To learn more, see Amazon RDS storage in the Amazon RDS User Guide.