RDS GP3 trying to increase IOPS and storage throughput - told to try again in 2 hours??

The need to wait before modifying IOPS and storage throughput on an Amazon RDS GP3 volume is related to the storage optimization process and the cooldown period between modifications.

When you make changes to your RDS instance's storage, including increasing IOPS or throughput, the system needs time to optimize and stabilize the new configuration. This process is designed to ensure the stability and performance of your database.

Typically, after making a storage modification, you need to wait at least six hours before you can make another change. This cooldown period allows the system to fully complete any ongoing optimization processes and ensure that the changes have been properly applied and stabilized.

The two-hour wait time you encountered might be a partial cooldown period, indicating that a recent modification was made and the system is still in the process of optimizing or stabilizing. The exact duration can vary depending on the size of your database and the extent of the changes being made.

During an actual upgrade, it's important to plan for this waiting period. If you anticipate needing to make multiple storage modifications, you should factor in these cooldown periods into your upgrade timeline. It's advisable to make any necessary storage changes well in advance of critical operations to avoid unexpected delays.

To minimize the impact during your actual upgrade:

1. Try to anticipate and implement any required storage changes ahead of time.
2. If possible, test the entire upgrade process, including storage modifications, in a non-production environment to understand the timing and any potential issues.
3. Consider reaching out to AWS support for guidance on your specific use case, especially if you have time-sensitive requirements during the upgrade process.

Remember, these waiting periods are in place to ensure the stability and performance of your database, so while they may cause some inconvenience, they are ultimately beneficial for the health of your RDS instance.
Sources
Modifying settings for General Purpose SSD (gp3) storage - Amazon Relational Database Service
Troubleshoot latency of EBS volumes in an RDS instance | AWS re:Post