VirtualCenter VMotion Requirements

To be configured for VMotion, each host in the cluster must meet the following requirements.

Shared Storage

Ensure that the managed hosts use shared storage. Shared storage is typically on a storage area network (SAN). See the VMware SAN Configuration Guide for additional information on SAN and the Server Configuration Guide for information on other shared storage.

Shared VMFS Volume

Configure all managed hosts to use shared VMFS volumes.

•	Place the disks of all virtual machines on VMFS volumes that are accessible by both source and target hosts.

•	Set access mode for the shared VMFS to public.

•	Ensure the VMFS volume is sufficiently large to store all virtual disks for your virtual machines.

•	Ensure all VMFS volumes on source and destination hosts use volume names, and all virtual machines use those volume names for specifying the virtual disks.

Note	Virtual machine swap files also need to be on a VMFS accessible to both source and destination hosts (just like .vmdk virtual disk files). Swap files are placed on a VMFS by default, but administrators might override the file location using advanced virtual machine configuration options.

Processor Compatibility

Ensure that the source and destination hosts have a compatible set of processors.

VMotion transfers the running architectural state of a virtual machine between underlying VMware ESX Server systems. VMotion compatibility therefore means that the processors of the target host must be able to resume execution using the equivalent instructions where the processors of the source host were suspended. Processor clock speeds and cache sizes might vary, but processors must come from the same vendor class (Intel versus AMD) and same processor family to be compatible for migration with VMotion.

Processor families such as Xeon MP and Opteron are defined by the processor vendors. You can distinguish different processor versions within the same family by comparing the processors’ model, stepping level, and extended features.

•	In most cases, different processor versions within the same family are similar enough to maintain compatibility.

•	In some cases, processor vendors have introduced significant architectural changes within the same processor family (such as 64-bit extensions and SSE3). VMware identifies these exceptions if it cannot guarantee successful migration with VMotion.

Note	VMware is working on maintaining VMotion compatibility across the widest range of processors through partnerships with processor and hardware vendors. For current information, contact your VMware representative.

Other Requirements

•	For ESX Server 3.0, the virtual machine configuration file for ESX Server hosts must reside on a VMFS.

•	VMotion does not currently support raw or undoable virtual disks or migration of applications clustered using Microsoft Cluster Service (MSCS).

•	VMotion requires a Gigabit Ethernet network between hosts.

•	VMotion requires a private Gigabit Ethernet migration network between all of the VMotion-enabled managed hosts. When VMotion is enabled on a managed host, configure a unique network identity object for the managed host and connect it to the private migration network.