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.
Amazon RDS storage volumes created from a snapshot during point-in-time recovery, snapshot restore, read replica creation, or Single-AZ to Multi-AZ conversion undergo volume initialization, in which the storage blocks from the snapshot must be 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 DescribeDBInstances API let you monitor your storage initialization progress in real time, so you can validate when all blocks have been written and 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 the Amazon Web Services China (Beijing) Region, operated by Sinnet and Amazon Web Services China (Ningxia) Region, operated by NWCD. To learn more about Amazon RDS storage, refer the Amazon RDS User Guide.