◆ Implement Microsoft Clustering Services to achieve high availability of individual virtual
machines. Note that versions of ESX Server prior to 3.5 were certified for support of
Microsoft server clusters in virtual machines. As of this writing, the recertification process
for clustering in a virtual machine was not complete. Please refer to the VMware website
for updated information about supported technologies.
◆ Implement VMware High Availability (HA) to provide automatic restart of virtual
machines residing on an ESX Server that fails.
◆ Use strict admission control for HA clusters unless virtual machine performance is not as
important as simply having the virtual machine powered on.
◆ Prioritize virtual machines for startup after server failure. Prepare a contingency plan
for powering off unnecessary virtual machines in the event of server failure, resulting in
reduced computing power.
◆ Implement a backup strategy that involves a blend of full virtual machine backups with file
level backups.
◆ Purchase enough backup agents to ensure minimal recovery times for servers with critical
production data. Schedule the backups to ensure that recovery times are appropriate
for the data type. For example, for data with greater value and a requirement for quicker
restore, backups should be scheduled more often than usual.
◆ Do not use virtual machine snapshots as long-term solutions to disaster recovery or business
continuity. Snapshots are meant as a temporary means of providing an easy rollback
feature and are used primarily for short term recovery purposes.
◆ Back up data as often as needed as determined by a written business continuity/disaster
recovery plan. More critical data should be backed up more often to prevent less data loss
in the event of disaster.
◆ Test the full and virtual machine backups regularly by restoring to a test or development
network.
◆ Store a copy of virtual machine backups in an off-site location. Otherwise, use tools to perform
virtual machine replication to distant datacenters. Virtualization offers significant
advantages in the realm of disaster recovery because virtual machines are encapsulated
into a discrete set of files.
◆ Purchase licenses for Windows Server 2003 Datacenter to achieve a greater return on
investment and achieve less stringent VMotion restrictions. Datacenter licenses allow for
the installation of an unlimited number of virtual machines per ESX Server host.