A file server system, including: - a network subsystem including a network interface module being communicably connectable to a network, the network interface module being configured to receive file service requests and respond to the file service requests over the network; - a file subsystem including a file system module being communicably connected with the network interface module for servicing the file service requests received at the network interface module; and - a storage interface module (15; 23) being communicably connected with the file system module (14; 22), the storage interface module (15; 23) being configured to convert output of the file system module (14; 22) into a format permitting access to a data storage system being communicably connected which the storage interface module (15; 23); wherein the file subsystem comprises a data bus arrangement being communicably connected with the network subsystem and the storage interface module (15; 23), the data bus arrangement including data buses (311, 312) for providing file content data to be stored in the data storage system and for retrieving file content data from the data storage system; wherein the storage interface module (15; 23) has a file content cache memory for storing file content data that is being read from and written to the data storage system; wherein the file server system is configured to handle the file content data along the data buses (311, 312) of the data bus arrangement, and the file system module is configured to use a control path that is distinct from the data buses (311, 312) of the data bus arrangement, and in this control path uses pointers to the file content data that is transported over the data buses (311, 312) of the data bus arrangement, the file system module comprising a communicably-linked series of separate hardware-implemented sub-modules (321, 322, 323, 324, 325) configured to handle tasks associated with file system management, wherein each sub-module of the file system module is configured to perform a distinct set of operations pertinent to processing of the file service requests received at the network interface module, and the file server system includes a plurality of metadata cache memories, each metadata cache memory being associated with a corresponding sub-module for storing metadata pertinent to the tasks of the respective sub-module without storing file content data to keep the metadata associated with a file system in metadata cache being distinct from the file content cache; wherein the communicably-linked series of separate sub-modules is hierarchically arranged and includes: - a non-volatile storage processing sub-module with associated non-volatile storage (NVRAM) for storing file system request data for subsequent storage in the data storage system, - a file sub-module for managing a data structure associated with file attributes, the file sub-module being communicably linked to the non-volatile storage processing sub-module, - a directory sub-module for handling directory management for the file sub-module, the directory sub-module being communicably linked to the file sub-module, - a tree sub-module for handling directory lookups for the directory sub-module, the tree sub-module being communicably linked to the directory sub-module, - an object store sub-module for causing storage and retrieval of file system objects in the data storage system, the object store sub-module being communicably linked to the tree sub-module, and - a free space allocation sub-module for retrieving and updating data pertinent to allocation of space in the data storage system, the free space allocation sub-module being communicably linked to the object store sub-module. - a network subsystem including a network interface module being communicably connectable to a network, the network interface module being configured to receive file service requests and respond to the file service requests over the network; - a file subsystem including a file system module being communicably connected with the network interface module for servicing the file service requests received at the network interface module; and - a storage interface module (15; 23) being communicably connected with the file system module (14; 22), the storage interface module (15; 23) being configured to convert output of the file system module (14; 22) into a format permitting access to a data storage system being communicably connected which the storage interface module (15; 23); - a non-volatile storage processing sub-module with associated non-volatile storage (NVRAM) for storing file system request data for subsequent storage in the data storage system, - a file sub-module for managing a data structure associated with file attributes, the file sub-module being communicably linked to the non-volatile storage processing sub-module, - a directory sub-module for handling directory management for the file sub-module, the directory sub-module being communicably linked to the file sub-module, - a tree sub-module for handling directory lookups for the directory sub-module, the tree sub-module being communicably linked to the directory sub-module, - an object store sub-module for causing storage and retrieval of file system objects in the data storage system, the object store sub-module being communicably linked to the tree sub-module, and - a free space allocation sub-module for retrieving and updating data pertinent to allocation of space in the data storage system, the free space allocation sub-module being communicably linked to the object store sub-module.