The requirement, 10 GB of disk space (table space, Oracle), has been added to the user guide.
It how has the following requirement:
APM Database System Requirements
The APM database requires the following minimum disk and memory requirements for APM data. Add extra capacity to meet the operating system and database requirements:
10 GB of disk space (table space, Oracle)
4 GB of RAM
If you are running only Introscope (no TIMs), verify that the computer has at least 2 GB of disk space and 1 GB of memory.
If you are running CA APM, we recommend that you put the APM database on its own disk or partition.