That AWS Aurora clusters have two types of storage
Aurora PostgreSQL clusters have:
Auto-scaling storage for persistent data (the “cluster volume”).
Local storage for temporary tables or files.
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
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
integer-type primary key field.