With multiple users using a Gluster volume to run their application, there is a possibility of security issues as the users can obtain other users information. With the subdirectory mount feature, a user can access only their part of the storage, and nothing more. This brings abstraction properly to multiple users consuming the storage. Mounting a part of the Gluster volume (i.e. a subdirectory) provides namespace isolation for users by separating out their directories. Thus, multiple users can use the storage without namespace collisions with other users.

For more information, see Mounting Volumes Manually in Red Hat Gluster Storage 3.3 Administration Guide.