Analyze the differences and pros and cons of two Exchange clusters

&http://www.aliyun.com/zixun/aggregation/37954.html ">nbsp; A server cluster is the pooling of many servers together for the same service, which looks like a single server to the client

A cluster can use multiple computers for parallel computing to achieve high computational speed, or it can be backed up with multiple computers, so that any one machine fails the entire system or it works. Once the Cluster service is installed and running on the server, the server can join the cluster. Clustering can reduce the number of single points of failure and enable high availability of clustered resources. The following sections briefly describe node behavior in cluster creation and cluster operations.

Note: For information about installing a clustered server, see the Help and Deployment Guide for the Windows Server 2003 product family.

Creating a Cluster

The cluster installation utility that is used to install the cluster software on the server and create a new cluster is included in the server cluster product. When you create a new cluster, you first run the utility on the computer that you selected as the first member of the cluster. The first step is to determine the cluster name and create the cluster database and the initial cluster member list to define the new cluster. A Windows Server 2003 cluster has added a Cluster Management Setup wizard and the ability to create, including from a remote, cluster using the Cluster.exe command line interface.

The second step in creating a cluster is to add a shared data storage device that can be used by all cluster members. This creates a new cluster with a node, its own local data storage device, and cluster shared resources-typically disk or data storage and connection media resources.

The final step in creating a cluster is to run the installation utility on every other computer that will be a member of the cluster. Whenever a new node is added to a cluster, the new node automatically obtains a copy of the existing cluster database from the original member of the cluster. When a node joins or forms a cluster, the Cluster service updates the private metabase copy of the node.

Form a cluster

If the server is running the Cluster service and cannot find other nodes in the cluster, it can form a cluster itself. To form a cluster, the node must be able to acquire exclusive rights to the quorum resource.

When the cluster is initially formed, the first node in the cluster will include the cluster configuration database. Each time a new node joins the cluster, the new node obtains and maintains a copy of the cluster configuration database locally. The quorum resource stores the latest version of the configuration database in the form of recovery logs, which contain node-independent cluster configuration and state data.

In a cluster operation, the Cluster service uses the quorum recovery log to perform the following actions:

Ensure that only one group of active, communicating nodes can form a cluster

Allows a node to form a cluster only if it can gain control of the quorum resource

Allow a node to join or remain in an existing cluster only if it can communicate with the node that controls the quorum resource

From the perspective of other nodes in the cluster and the Cluster service management interface, each node in the cluster may be in one of three different states when the cluster is formed. These states are logged by the event handler, which the event log manager replicates to other nodes in the cluster. The Cluster service status includes:

Offline。 The node at this time is not a fully valid cluster member. The node and its cluster server may or may not be running.

Online。 The node at this time is a fully valid cluster member. It complies with the update of the cluster database, exerts its own influence on the quorum algorithm, maintains heartbeat traffic, and can own and run resource groups.

Time out. The node at this time is a fully valid cluster member. It complies with the update of the cluster database, exerts its own influence on the quorum algorithm, and maintains heartbeat traffic, but it cannot accept resource groups. It can only support those resource groups that it currently owns. The paused state is provided to allow certain maintenance to be performed. Most server cluster components treat online and paused as equivalent states.

If you're considering creating an Exchange server cluster, one of the big decisions you have to make is to consider creating a active cluster or a active/passive cluster. In this article, I'll explain the differences between the two Exchange cluster patterns and their pros and cons.

The difference between active/passive and active clusters is in the number of cluster nodes used. At least one node in the active/passive cluster configuration acts as a hot standby. The hot standby only works when the failure transfer occurs. In the active configuration, each cluster node will run one or more Exchange virtual servers.

Although this is a very simple statement (and it does), you need to be aware of many of these limitations. The biggest limitation is related to the Exchange Virtual server, which is the number of logical Exchange Servers your cluster is running.