6.5.1

Table Of Contents
n
“Migrate a Virtual Machine to New Storage,” on page 137
n
“Place vMotion Trac on the vMotion TCP/IP Stack of an ESXi Host,” on page 138
n
“Place Trac for Cold Migration, Cloning, and Snapshots on the Provisioning TCP/IP Stack,” on
page 140
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“Limits on Simultaneous Migrations,” on page 141
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About Migration Compatibility Checks,” on page 142
Cold Migration
Cold migration is the migration of powered o or suspended virtual machines between hosts across
clusters, data centers, and vCenter Server instances. By using cold migration, you can also move associated
disks from one datastore to another.
You can use cold migration to have the target host checked against fewer requirements than when you use
vMotion. For example, if you use cold migration when a virtual machine contains a complex application
setup, the compatibility checks during vMotion might prevent the virtual machine from moving to another
host.
You must power o or suspend the virtual machines before you begin the cold migration process. Migrating
a suspended virtual machine is considered a cold migration because although the virtual machine is
powered on, it is not running.
CPU Compatibility Check During Cold Migration
If you aempt to migrate a powered o virtual machine that is congured with a 64-bit operating system to
a host that does not support 64-bit operating systems, vCenter Server generates a warning. Otherwise, CPU
compatibility checks do not apply when you migrate powered o virtual machines with cold migration.
When you migrate a suspended virtual machine, the new host for the virtual machine must meet CPU
compatibility requirements. This requirement allows the virtual machine to resume execution on the new
host.
Operations During Cold Migration
A cold migration consists of the following operations:
1 If you select the option to move to a dierent datastore, the conguration les, including the NVRAM
le (BIOS seings), log les, and the suspend le, are moved from the source host to the destination
host’s associated storage area. You can choose to move the virtual machine's disks as well.
2 The virtual machine is registered with the new host.
3 After the migration is completed, the old version of the virtual machine is deleted from the source host
and datastore if you selected the option to move to a dierent datastore.
Network Traffic for Cold Migration
By default, data for VM cold migration, cloning, and snapshots is transferred through the management
network. This trac is called provisioning trac. It is not encrypted but uses run-length encoding of data.
On a host, you can dedicate a separate VMkernel network adapter to the provisioning trac, for example, to
isolate this trac on another VLAN. On a host, you can assign no more than one VMkernel adapter for
provisioning trac. For information about enabling provisioning trac on a separate VMkernel adapter, see
the vSphere Networking documentation.
Chapter 11 Migrating Virtual Machines
VMware, Inc. 115