AWS responded. TLDR; be patient, all is well.
Thank you for contacting the AWS Premium Support Database team, my name is Kajol and its my pleasure to assist you with this case today.
I understand you have concerns regarding scaling up your instance class from db.m4.2xlarge to db.m5.2xlarge on a multi AZ RDS instance ‘treeherder-prod’ and it is still in modifying. I will be happy to check on it for you.
I looked into the RDS instance ‘treeherder-prod’ and I can confirm that the API call was registered for modifying instance class at 2019-07-03 16:37:20 UTC. I can also confirm the following events which states that MAZ failover completed successfully and hence 60-120 sec of downtime.
2019-07-03 16:46:17 UTC Multi-AZ instance failover completed User
2019-07-03 16:45:41 UTC DB instance restarted User
2019-07-03 16:45:32 UTC Multi-AZ instance failover started. User
2019-07-03 16:45:06 UTC DB instance shutdown User
2019-07-03 16:37:42 UTC Applying modification to database instance class User
Currently your instance is available to use but the modifying status is because of the secondary. Looking further I could see that secondary is still being scaled up. Further checking the workflows and all details and researching on it, I can see that the secondary instance was having capacity issues in that Availability zone to scale to db.m5.2xlarge and hence had to be moved to different AZ and thus not only the underlying host but also volumes had to be replaced to be placed in the AZ and thus it is taking time.
With growing capacity’s we would want our customer to be in AZ with sufficient resources and hence this step is important and is taking a little while, it is not normal and occurs on a rare basis, no action is required from your end. I can confirm that the execution is progressing smoothly and its not stuck, please wait for a while and it should complete.
Hope this answers your question. Please reach out to me, should you have any further questions or concerns. I will be happy to help you resolve your issue.
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