HP recommends that you allocate 4 GB of storage for every 100 workloads you will manage with gWLM. With a 5-minute sampling interval, this is enough space to store 2 years of data, which you can then use for capacity planning and performance management.
On HP-UX, the provided HP System Management Database (HPSMDB), also known as PostgreSQL, stores its data in the /var/opt/ file system. On HP-UX and Windows systems using Oracle, set aside the space in the file system used by the configured database.