Internally, a production file system and each of its related snapshot file
systems have a common file system identifier (fid') and a unique
respective file system identifier (fsid'). Externally, the production
file system and each of its related snapshot file systems has a common
file system identifier (fsid) and a unique respective file identifier
(fid). For example, the "fsid" and "fid" for the production and snapshot
file systems are interchanged between a client-server protocol layer and
a logical volume layer in a file server. Moreover, the file handle for an
object indicates whether an object is in either a production file system
that is not configured to have related snapshots, a production file
system that is configured to have related snapshots, or a snapshot file
system. When the object is in a snapshot file system, the file handle
also indicates the related production file system.