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 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.