On , I learnt ...

That AWS Aurora clusters have two types of storage

Aurora PostgreSQL clusters have:

There’s further information in the AWS docs

The amount of local storage space is tied to the instance class — more space can only be obtained by upgrading. The amount of local storage for each instance type doesn’t seem to be published anywhere. Based on CloudWatch metric data, a db.r6g.xlarge instance has 50G; this Reddit thread has some values for instance classes in the r4 series.

Beware that the relatively small amount of local storage can be a problem for large table operations like changing the type of a column. We found to our cost that 50G wasn’t enough space to run a query like:

ALTER TABLE some_large_table ALTER COLUMN id TYPE bigint;

which was required as the table had exhausted all 2.7 billion IDs available to an integer-type primary key field.