Logical and Physical Cluster Components

The Cluster service manages applications by controlling logical and physical cluster components.

Logical Components The Cluster service manages a variety of logical components, including the following:

■ Virtual server Consists of a servername together with groups of resources needed to run a clustered application. The virtual server is the clients' view of the clustered server, as the clients are unaware of which cluster node is hosting the virtual server.

Object

Basic Syntax

Cluster

cluster [[/cluster:]cluster_name] /option

Cluster node

cluster [[/cluster:]cluster_name] node node_name /option

Cluster group

cluster [[/cluster:]cluster_name] group group_name [/node:node_

name] /option

Cluster network

cluster [[/cluster:]cluster name] network network name /option

Cluster netinterface

cluster [[/cluster:]cluster name] netinterface /node: node name / network: network name /option

Cluster resource

cluster [[/cluster:]cluster_name] resource resource_name /option

Cluster resourcetype

cluster [[/cluster:]cluster_name] resourcetype resource_type_ display_name /option

Table 24-2. Basic Syntax for Cluster.exe

■ Resources The basic elements managed by the Cluster service. The definition of any given resource may correspond to a physical device (such as a disk drive) or a logical entity (such as an IP address, a service, or a name). Resources have attributes that, among other things, specify which nodes are allowed to bring the resource online, along with the prerequisites that a cluster node must have online before it may bring the given resource online.

■ Groups A collection of resources, and any specific resource may belong to only one group at a time. During failover and failback, the Cluster service moves a group from one cluster node to another, ensuring that all the resources of a group are offline to the old cluster node before any of the resources are brought online on the new cluster node. An operation performed on a group affects all of the resources within the group.

Physical Components Physical components support the cluster's logical components, and include the following:

■ Nodes A server that is a member of the cluster. A node is said to be online when the server is running, the Cluster service is running on it, and the node is in communication with other online nodes.

■ Cluster disks Logical disks (either individual physical disks or RAID volumes) that reside on a shared bus accessible by all the nodes of the cluster. Cluster disks host application data. When you are preparing cluster disks, be sure to configure them as basic disks, not dynamic disks.

■ Quorum resource A disk drive on a shared bus that is not a member of any failover group. The Cluster service places management data and the recovery log on the quorum resource, and uses it to arbitrate control of the cluster. The quorum resource on a shared bus disk drive must be configured as a Basic disk, not a Dynamic disk.

■ Heartbeats IP packets exchanged regularly by cluster nodes. When a node fails to receive a heartbeat packet from another node, it assumes that the nonsending node has failed. An active node then initiates the failover process.

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Responses

  • iggi abrha
    Is cluster name logical or physcal?
    7 years ago
  • angelina
    Is cluster a physical or logical thing?
    7 years ago
  • jessica
    What are the physical components in cluster?
    7 years ago

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