Does increase in database size needs an increase in instance class?? like from t1 to t3

Hello.

Database disk space cannot be increased simply by increasing the instance type.
If you are hosting your database on EC2, you will need to increase the EBS size.
Please increase the EBS size by following the steps in the document below, and then expand the disk file on the OS side.
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/requesting-ebs-volume-modifications.html
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/recognize-expanded-volume-linux.html

If you are hosting on RDS, you can increase the number from the database change screen.
It is also possible to perform automatic scaling, so please set it as necessary.
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_PIOPS.StorageTypes.html

Hi,

To make a better choice, you may be interested in this very detailled post about instance class and type: https://blog.guilleojeda.com/aws-rds-instance-types-complete-guide

Best,

Didier