Abstract: An apparatus, system, and method for managing an object-based file system, and in particular for providing modifying access to an external application to a file system being managed in a user access restricted state, such as e.g. in the read only state. The apparatus including a network interface configured to communicably connect to one or more client computers via a communication network, and a file system management section, implemented at least in part by processor, configured to manage the object-based file system comprising plural file objects, each file object being associated with a respective file of the file system, the file system management section being configured to serve file access requests of a file serving protocol received via the interface. The file system management section is further configured to provide a block access object of the object-based file system being mountable as a block storage device.