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

Delegation Stackable Module for Local Access

NFSv4 clients support delegation on HP-UX 11i v3. However, until the release of HP-UX 11i v3

ONCplus version B.11.31.03, NFSv4 servers support delegation with the caveat that no local file

access should occur on any delegated file. For example, if the server grants a delegation to the file

“/a/b/foo” then any local users on the server need to avoid accessing file “foo” while the delegation

is in effect. If both local and remote users modify the delegated file then the data in “foo” could

become corrupted.

With HP-UX 11i v3 ONCplus version B.11.31.03, support was added for local file access with

delegations through a file system stackable module called nfs4deleg. This module provides a way to

recall delegations issued by the NFS server when a file is modified locally on a machine by

intercepting the local operation which triggers a callback to recall the delegation from the NFS client.

The NFS client will write out locally cached data to the server before returning the delegation.

Using the nfs4deleg stackable module requires special configuration of the physical file system on the

NFSv4 server.

• Create a volume and new file system to mount the stackable module.

# lvcreate –L <size> <volgrp>

# mkfs –F vxfs <volume created>

• Create a text file containing the nfs4deleg stackable module name.

# echo “nfs4deleg” > <filename>

• Create a stackable module template using fstadm(1M).

# fstadm create –f <filename> –n <template>

This will create a template with the name <template>

• Mount the newly created file system with the nfs4deleg stackable module.

# mount –F vxfs –o stackfs=<template> <volume created> <directory>

• Share the new file system that has been mounted with the nfs4deleg module.

# share <directory>