VMware GSX 3 - Manual (Page 204)

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204
VMware GSX Server Administration Guide
Overview of Clustering with GSX Server
GSX Server clustering capabilities are ideally suited for development, testing and
training applications.
Note: Always rigorously test and review your cluster before deploying it in a
production environment.
This section includes:
• Applications That Can Use Clustering on page 205
• Clustering Software on page 205
Clustering is providing a service via a group of servers to get high availability,
scalability or both.
For example:
• In a Web server cluster where the Web site serves static content, a gateway
distributes requests to all nodes according to load. The gateway also redirects
requests to remaining nodes if one crashes.
This configuration increases availability and performance over a single-machine
approach. Network Load Balancing in Windows 2000 and Windows Server 2003
provides such a service.
• In a more complex cluster, a single node might serve a database. If that node
crashes, it must restart the database on another node. The database application
knows how to recover from a crash. In normal operation, other nodes run other
applications.
Microsoft Cluster Service and Veritas Cluster Service provide such a service.
In a typical virtual machine cluster:
• Each virtual machine is one node in the cluster.
• Disks are shared between nodes.
Shared disks are needed if the application uses dynamic data as mail servers or
database servers do.
When using virtual disks, you must preallocate the disk space at the time you
create the virtual disk.
• There are extra network connections between nodes for monitoring heartbeat
status.
• There is a method for redirecting incoming requests.