vCenter Server places limits on the number of simultaneous virtual machine migration and provisioning operations that can occur on each host, network, and datastore.

Each operation, such as a migration with vMotion or cloning a virtual machine, is assigned a resource cost. Each type of resource, such as host, datastore, or network, has a maximum cost that it can support at any one time. Any new migration or provisioning operation that would cause a resource to exceed its maximum cost does not proceed immediately, but is queued until other operations complete and release resources. Each of the network, datastore, and host limits must be satisfied for the operation to proceed.

vMotion without shared storage is a combination of vMotion and Storage vMotion and inherits the network, host, and datastore costs associated with those operations. When you consider per-operation costs, vMotion without shared storage becomes equivalent to a Storage vMotion with a network cost of 1.

Network limits apply to migrations with vMotion. Network limits depend on both the version of ESXi and the network type.

Network Limits for Migration with vMotion

Operation

ESX/ESXi Version

Network Type

Maximum Cost

vMotion

3.x

1GigE and 10GigE

2

vMotion

4.0

1GigE and 10GigE

2

vMotion

4.1, 5.0, 5.1

1GigE

4

vMotion

4.1, 5.0, 5.1

10GigE

8

All migrations with vMotion have a network resource cost of 1.

Datastore limits apply to migrations with vMotion and with Storage vMotion. A migration with vMotion involves one access to the datastore. A migration with Storage vMotion involves one access to the source datastore and one access to the destination datastore.

Datastore Limits for Migration with vMotion and Storage vMotion

Operation

ESX/ESXi Version

Maximum Cost

vMotion/Storage vMotion

3.x

8

vMotion/Storage vMotion

4.0

8

vMotion/Storage vMotion

4.1, 5.0, 5.1

128

Datastore Resource Costs for vMotion and Storage vMotion

Operation

ESX/ESXi Version

Datastore Resource Cost

vMotion

3.x, 4.0, 4.1, 5.0, 5.1

1

Storage vMotion

3.x

1

Storage vMotion

4.0

1

Storage vMotion

4.1, 5.0, 5.1

16

Host limits apply to migrations with vMotion, Storage vMotion, and other provisioning operations such as cloning, deployment, and cold migration. All hosts have a maximum cost per host of 8. For example, for an ESXi 5.0 host, you can perform 2 Storage vMotion operations, or 1 Storage vMotion and 4 vMotion operations.

Host Migration Limits and Resource Costs for vMotion, Storage vMotion, and Provisioning Operations

Operation

ESX/ESXi Version

Derived Limit Per Host

Host Resource Cost

vMotion

3.x, 4.0

2

4

vMotion

4.1, 5.0, 5.1

8

1

Storage vMotion

3.x, 4.0, 4.1, 5.0, 5.1

2

4

vMotion Without Shared Storage

5.1

2

4

Other provisioning operations

3.x, 4.0, 4.1, 5.0, 5.1

8

1