3.1.2 MxFS-Linux Administration Guide

Chapter 1: Introduction 4

Export Records

An export record is equivalent, indeed exactly equal to, the individual

records contained in the /etc/exports file of a traditional NFS server. The

format of the record and the options available are precisely the same in

form and function.

Each record identifies a filesystem and directory sub-tree to be exported

via NFS, the list of clients authorized to mount and access the specified

filesystem sub-tree, and the options that modify how the filesystem

sub-tree will be shared with clients (e.g., read-write or read-only; many

other options exist). Free-form user comments can also be included with

an export record.

The contents of an existing /etc/exports file can be imported unchanged

into a given Export Group. It is also possible to enter and edit individual

export records directly on the Management Console. The filesystem

sub-tree, shared via NFS, is referred to as an export.

Virtual NFS Services

A Virtual NFS Service is a virtual host (a Matrix Server

VHOST) that is

dedicated to NFS file service. Its primary purpose is to associate a

“virtualized” IP address with an Export Group and to ensure, for high

availability, that this virtualized IP address and the associated Export

Group and NFS service are always available on one node of the cluster. A

virtualized IP address is a portable IP address that can be moved from

one node in the cluster to another when a failover action occurs.

A virtualized IP address, an associated Export Group, a “primary” cluster

node, and a list of “backup” cluster nodes constitute a highly available

Virtual NFS Service. NFS clients connected via the virtualized IP address

will always remain connected to their Virtual NFS Service (with the same

filesystem exports) regardless of any failover transitions, from one node

to another, of the Virtual NFS Service.

When creating a Virtual NFS Service, the administrator specifies an

unused network address that NFS clients will use to connect to the highly

available Virtual NFS Service. This address must be on the same subnet as

one of the networks already in use in the cluster. The administrator then

specifies both a primary node to host the Virtual NFS Service and an