RDS Storage upgrade - failure Error: Error modifying DB Instance: InvalidParameterCombination: Invalid storage size for engine name postgres and storage type gp2: 2400

Question

When we are attempting to upgrade the storage on our RDS instance from 2200GB to 2400GB we are met with the following error. This is strange as I thought there were no storage limitations in an upgrade for non-autoscaling storage.

```
InvalidParameterCombination: Invalid storage size for engine name postgres and storage type gp2: 2400
```

What are the minimum values we can upgrade an RDS instances storage by?

kentrad · Accepted Answer

According to the documentation, [Working with storage for Amazon RDS DB instances](https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_PIOPS.StorageTypes.html):

"When you increase the allocated storage, it must be by at least 10 percent. If you try to increase the value by less than 10 percent, you get an error."

Increase it by 220.

D-Rao · Answer

Note that the error indicates that the target storage size is invalid. When you increase the allocated storage, it must be by at least 10 percent. If you try to increase the value by less than 10 percent, you get an error. Try with a bigger increment and it should work.

Good luck!

WillCrossland · Answer

I solved this by first bumping the storage from 200 to 500 and max storage from 400 to 800. We then were able to adjust the instance type from "db.m6g.xlarge" to "db.t4g.medium" without issue. Actually at 1st  "db.t4g.medium" was not even an available option in the AWS console until we adjusted the storage. We saw this error when trying to change the instance type and storage at the same time via terraform.

RDS Storage upgrade - failure Error: Error modifying DB Instance: InvalidParameterCombination: Invalid storage size for engine name postgres and storage type gp2: 2400

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