"Max storage size not supported" When Upgrading AWS RDS

Question

I am using db.m5.4xlarge but our users increase lot so the server is going too slow, we want to upgrade RDS to db.m5.8xlarge, But when I try to upgrade RDS, it gave me an error (Max storage size not supported).

Answer 1

Judged on discussion with you I think it might actually be more beneficial for you to take a look at creating read replicas rather than an ever growing instance.

The problem with increasing the instance as you are are now is that everytime it will simply reach another bottleneck and it becomes a single point of failure.

Instead the following strategy is more appropriate and may end up saving you cost:

• Create read replicas in RDS to handle all read only SQL queries, by doing this you are going to see performance gains over your current handling. You might even be able to scale down the write cluster.
• As your application is read heavy look at using caching for your applications to avoid heavy read usage. AWS provides ElastiCache a a managed service using either Redis or MemcacheD as the caching service. This again could save you money as you won't need as many live reads.

If you choose to include caching too take a look at these caching strategies to work out how you would want to use it.

Answer 2

I think the reason is that, unlike db.m5.4xlarge, db.m5.8xlarge does not support MySQL. From docs: