1. A device comprising: a receiver configured to receive a join-lookup remote procedural call (RPC) for a file, wherein the join-lookup RPC requests a join operation of sub-files associated with the file, wherein the join-lookup RPC comprises arguments, wherein the arguments comprise a first parameter referring to a number of files to look up and join, a second parameter referring to a type of join operation to perform, a third parameter referring to names of the files to look up and join, and a fourth parameter referring to offset or other related information, wherein the join-lookup RPC is associated with a modified file open layer operation, a virtual file system (VFS) join-lookup layer operation, and a Network File System (NFS) join-lookup layer operation, wherein the VFS join-lookup layer operation is at a lower layer than the modified file open layer operation, and wherein the NFS join-lookup layer operation is at a lower layer than the VFS join-lookup layer operation; a transmitter configured to transmit the file in response to the Join-Lookup RPC; a memory; a sandbox associated with a portion of the memory and configured to: retrieve the sub-files from system disks, load the sub-files, and perform the join operation, wherein the device is a distributed file system (DFS) network-attached storage (NAS) server configured to implement an NFS protocol; and a hypervisor configured to create and run the sandbox.