6.7

Table Of Contents
Ensure that the managed hosts use shared storage. Shared storage is typically on a SAN, but can also
be implemented using NAS shared storage.
See the vSphere Storage documentation for information about other shared storage.
Shared VMFS Volume Requirements
A DRS cluster has certain shared VMFS volume requirements.
Configure all managed hosts to use shared VMFS volumes.
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Place the disks of all virtual machines on VMFS volumes that are accessible by source and
destination hosts.
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Ensure the VMFS volume is sufficiently large to store all virtual disks for your virtual machines.
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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 source and destination hosts
(just like .vmdk virtual disk files). This requirement does not apply if all source and destination hosts are
ESX Server 3.5 or higher and using host-local swap. In that case, vMotion with swap files on unshared
storage is supported. Swap files are placed on a VMFS by default, but administrators might override the
file location using advanced virtual machine configuration options.
Processor Compatibility Requirements
A DRS cluster has certain processor compatibility requirements.
To avoid limiting the capabilities of DRS, you should maximize the processor compatibility of source and
destination hosts in the cluster.
vMotion transfers the running architectural state of a virtual machine between underlying ESXi hosts.
vMotion compatibility means that the processors of the destination 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 the same processor family to be compatible for migration with vMotion.
Processor families 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.
Sometimes, 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.
vSphere Resource Management
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