Introducing Network File System Version 4 on HP-UX 11i v3

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Figure 5. nfsstat NFSv4 output
The output displays not just the NFSv4 procedures, NULL and COMPOUND, but also all opcodes that
can be sent as part of a COMPOUND procedure. The opcodes listed include GETFH (line 8),
PUTROOTFH (line 18), and SETCLIENTID (line 24). These opcodes were used in the initial mount
request seen in Figure 1 and in identifying the client as seen in Figure 3. See the RFC for details on
SETCLIENTID_CONFIRM.
Some other opcodes of interest in Figure 5 are file-open related opcodes, OPEN (line 14) and CLOSE
(line 4), and locking-related opcodes, LOCK, LOCKT, and LOCKU (line 10).
Open and close
Other important stateful operations in NFSv4 are file opens and closes. Figure 6 shows the Ethereal
trace generated after an open() system call was made.
On an OPEN, the server returns a state identifier that identifies this instance of this client’s file open.
The state associated with this file open is maintained on the server.
The client identification returned to the client by the server is validated on each NFSv4 operation.