I found a similar thread this is related to, but it's a slightly different problem.
We have an RDS Mysql database that is set to autoscale, but it also has storage notifications turned on. We've found through empirical evidence that the threshold for storage notifications is probably set to <= 10% (less than or equal to) of database size and the threshold for autoscaling is set to < 10% (less than). is it possible to get these to line up? ( either change the threshold for autoscaling to <= 10% or the notification threshold to < 10% ?
our database grows relatively slowly, and it takes about a week and a half for us to go from 10.5% of the storage down to 10% of the storage, at an email every 2 hours, that's ~120 emails that we're low on storage space before the auto-scaling kicks in.
The free storage capacity for DB Instance: databaseName is low at 10% of the provisioned storage [Provisioned Storage: 161.18 GB, Free Storage: 16.51 GB]. You may want to increase the provisioned storage to address this issue.
yeah we don't have AWS support with our account, which is why i'm posting here.