The WebNFS service makes files in a directory available to clients by using a public file handle. A file handle is an address that is generated by the kernel that identifies a file for NFS clients. The public file handle has a predefined value, so the server does not need to generate a file handle for the client. The ability to use this predefined file handle reduces network traffic by eliminating the MOUNT protocol. This ability should also accelerate processes for the clients.
By default, the public file handle on an NFS server is established on the root file system. This default provides WebNFS access to any clients that already have mount privileges on the server. You can change the public file handle to point to any file system by using the share command.
When the client has the file handle for the file system, a LOOKUP is run to determine the file handle for the file to be accessed. The NFS protocol allows the evaluation of only one path name component at a time. Each additional level of directory hierarchy requires another LOOKUP. A WebNFS server can evaluate an entire path name with a single multicomponent lookup transaction when the LOOKUP is relative to the public file handle. Multicomponent lookup enables the WebNFS server to deliver the file handle to the desired file without exchanging the file handles for each directory level in the path name.
In addition, an NFS client can initiate concurrent downloads over a single TCP connection. This connection provides quick access without the additional load on the server that is caused by setting up multiple connections. Although web browser applications support concurrent downloading of multiple files, each file has its own connection. By using one connection, the WebNFS software reduces the overhead on the server.
If the final component in the path name is a symbolic link to another file system, the client can access the file if the client already has access through normal NFS activities.
Normally, an NFS URL is evaluated relative to the public file handle. To change the evaluation to be relative to the server's root file system, add an additional slash to the beginning of the path. The following two NFS URLs are equivalent if the public file handle has been established on the /export/ftp file system.