6.5.1

To determine the maximum number of concurrent vMotion operations possible, see “Limits on
Simultaneous Migrations,” on page 141. These limits vary with a host's link speed to the vMotion network.
Round-Trip Time for Long-Distance vMotion Migration
If you have the proper license applied to your environment, you can perform reliable migrations between
hosts that are separated by high network round-trip latency times. The maximum supported network
round-trip time for vMotion migrations is 150 milliseconds. This round-trip time lets you migrate virtual
machines to another geographical location at a longer distance.
Multiple-NIC vMotion
You can congure multiple NICs for vMotion by adding two or more NICs to the required standard or
distributed switch. For details, see the VMware KB article at hp://kb.vmware.com/kb/2007467.
Network Configuration
Congure the virtual networks on vMotion enabled hosts as follows:
n
On each host, congure a VMkernel port group for vMotion.
To have the vMotion trac routed across IP subnets, enable the vMotion TCP/IP stack on the host. See
“Place vMotion Trac on the vMotion TCP/IP Stack of an ESXi Host,” on page 138.
n
If you are using standard switches for networking, ensure that the network labels used for the virtual
machine port groups are consistent across hosts. During a migration with vMotion, vCenter Server
assigns virtual machines to port groups based on matching network labels.
N By default, you cannot use vMotion to migrate a virtual machine that is aached to a standard
switch with no physical uplinks congured, even if the destination host also has a no-uplink standard
switch with the same label.
To override the default behavior, set the
config.migrate.test.CompatibleNetworks.VMOnVirtualIntranet advanced seings of vCenter Server to
false. The change takes eect immediately. For details about the seing, see VMware knowledge base
article at hp://kb.vmware.com/kb/1003832. For information about conguring advanced seings of
vCenter Server, see “Congure Advanced Seings,” on page 50.
For information about conguring the vMotion network resources, see “Networking Best Practices for
vSphere vMotion,” on page 119.
vCenter Server and Host Management
118 VMware, Inc.