Windows Integrity Cluster Installation and Configuration Guide

Introduction

Cluster terminology

Chapter 1

Resource state changes can occur either manually (when you use Cluster Administrator

to make a state transition) or automatically (during the failover process). When a group

is failed over, the states of each resource are altered according to their dependencies on

the other resources in the group.

Resource dependencies

A dependency is a reliance between two resources that makes it necessary for both

resources to run on the same node (for example, a Network Name resource depending on

an IP address). The only dependency relationships that Cluster service recognizes are

relationships between resources. Cluster service cannot be told, for example, that a

resource depends on a Windows 2003 service; the resource can only be dependent on a

resource representing that service.

Groups

Groups are a collection of resources to be managed as a single unit for configuration and

recovery purposes. Operations performed on a group, such as taking it offline or moving

it to another node, affect all resources contained within that group. Usually a group

contains all the elements needed to run a specific application, and for client systems to

connect to the service provided by the application.

If a resource depends on another resource, each of the resources must be a member of the

same group. In the example of the file share resource, the group containing the file share

must also contain the disk resource and network resources such as the IP address and

NetBIOS name to which clients connect to access the share. All resources within a group

must be online on the same node in the cluster.

NOTE During failover, entire groups are moved from one node to another in the cluster. A single

resource cannot fail from one node to another.

Quorums

Each cluster has a special resource known as the quorum resource. The quorum

provides a means for arbitration leading to node membership and cluster state decisions.

Only one node at a time may own the quorum. That node is designated as the primary

node. When a primary node fails over to a backup node, the backup node takes

ownership of the quorum.

The quorum resource also provides physical storage to maintain the configuration

information for the cluster. This information is kept in the quorum log, which is simply a

configuration database for the cluster. The log holds cluster configuration information

such as which servers are part of the cluster, what resources are installed in the cluster,

and what state those resources are in (for example, online or offline). By default the

quorum log is located at \MSCS\quolog.log.

NOTE Quorums are only used in the Microsoft Cluster Service known as Server Cluster (they

are not used in Network Load Balancing). Therefore, references to quorums throughout

the remainder of this document apply to Server Clusters only.