The same core technology is, however, used to implement all of these forms of persistent data storage and all of the interfaces are ultimately supported by the same server processes.
The concept of volumes in AFS has some strong similarity from the point of the view of users, although the implementation in MapR FS is completely different.
Similar mechanisms are used to allow a Filesystem in Userspace (FUSE) interface and an approximate emulation of the Apache HBase API.
A volume is a special data structure similar to a directory in many ways, except that it allows additional access control and management operations.
Proprietary technology is used in MapR FS to implement transactions in containers and to achieve consistent crash recovery.