Specifications

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VMware GSX Server Administration Guide
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.
Applications That Can Use Clustering
To take advantage of clustering services, applications need to be clustering-aware.
Such applications can be stateless, such as Web servers and VPN servers. Clustering-
aware applications often include built-in recovery features, like those in database
servers, mail servers, file servers or print servers.
Clustering Software in Virtual Machines
Available clustering software includes:
• Microsoft Clustering Service (MSCS) — which provides fail-over support for two
to four-node clusters for applications such as databases, file servers and mail
servers.
• Microsoft Network Load Balancing (NLB) — that balances the load of incoming
IP traffic across a cluster of up to 32 nodes for applications such as Web servers
and terminal services.
• Veritas Clustering Service (VCS).
• Novell Clustering Services.
Note: These clustering services are tested and supported by VMware only with
Windows host operating systems.