General Parallel File System (GPFS) is a distributed filesystem developed and owned by IBM. This is a proprietary and closed source storage system, which limits its appeal and adaptability. Licensing and support cost added to that of storage hardware add up to an expensive solution. Moreover, it has a very limited set of storage interfaces: it provides neither block storage (like RBD) nor RESTful (like RGW) access to the storage system, limiting the constellation of use-cases that can be served by a single backend.
In 2015 GPFS was rebranded as IBM Spectrum Scale.