Certain JBoss ON features can have a significant impact on storage requirements. Anything that relates to storing content in the JBoss ON database — configuration drift snapshots, bundle versions, and content-backed resources like WARs — increases the storage requirements.
JBoss ON stores all versions of content. Therefore, the system which hosts the backend database (Oracle or PostgreSQL) must have enough disk space to store all versions of all content for any resources using drift monitoring, content updates, and bundles. Additionally, the database itself must have adequate tablespace for the content.
When calculating the required amount of space, estimate the size of every artifact (bundle, web application, monitored directory), and then the number of versions for each artifact. At a minimum, have twice that amount of space available; both PostgreSQL and Oracle require twice the database size to perform cleanup operations like vacuum, compression, and backup and recovery.