Perform this task to change the host where a VM runs, or change the storage pool that stores disks (image files) of a VM. You can perform online migration to migrate a VM in running or suspended state, or perform offline migration to migrate a VM in shutdown state. VM migration includes the following types:
Dynamic migration—VMs are dynamically migrated in a cluster when they are running. Dynamic migration occurs when hosts fail, resources are allocated unevenly, or DPM policies are configured. Dynamic VM migration is implemented through HA, DRS, and DPM configuration of a cluster.
Manual migration—VMs are migrated manually by an administrator. Manual migration is performed during maintenance to optimize system performance. For example, you can manually migrate the VMs on a host before you upgrade the hardware of the host. After hardware upgrade, you can migrate the VMs back to the host.
To avoid migration failure, make sure the target storage pool has sufficient space.
To avoid VM startup failure or slow VM startup after migration, make sure the target host has sufficient CPU and memory resources. Online VM migration affects the memory and CPU performance of the host and might cause service interruption. Please be cautious. As a best practice, do not perform online VM migration during peak service periods.
For the Storage migration type and the Host and Storage migration type, make sure the available space in the source storage pool is larger than the total capacity of the VM's storage volumes. If you change the disk format in migration, make sure the available space of the target storage is at least twice the space of the source storage. Violation of this restriction might cause migration failure. Migrating the data storage of a VM affects the memory, CPU, and disk I/O performance of the host. Please be cautious. As a best practice, do not migrate the data storage for multiple VMs in bulk during peak service periods.
On the top navigation bar, click VMs.
Select a VM, click More on the VM tile, and then select Migrate, or select a VM from the navigation pane to enter the VM overview page, and then click Migrate.
Set the parameters as described in "Parameters" to complete VM migration.
Migration Type
Host: Migrate a VM to another host. This method applies to VMs that use shared storage pools. The target host and the destination host must use the same shared storage pool.
Storage: Change the storage used by a VM.
Host and Storage: Migrate a VM to another host and change the VM storage. The target host can be any host in UIS Manager.
Timeout: Specify the timeout period for the migration of a running VM. The system suspends the VM when the VM is not migrated before the migration timeout expires to speed up migration. After migration, the system resumes the VM automatically. If you set the migration timeout to 0, the system does not suspend the VM during migration.
The migration timer is triggered depending on the migration mode.
Change Host/Change Host and Storage—The timer is triggered when the VM starts to be migrated.
Change Storage—The timer is triggered when the system updates dirty data (data generated during migration) of the first disk on the VM after all target disks have been migrated to the target storage pool.
Compress: Set whether to compress the data to be transmitted during migration. This parameter is applicable only to running and suspended VMs.
Encryption: Select whether to encrypt the tunnel between the source and destination hosts. This parameter is applicable only to running and suspended VMs and is available only when the migration type is Change Host or Change Host and Storage.
Destination Storage
Set Format: Specify the disk format. If the disk of a VM has base image files, the disk format cannot be changed.
Unchanged—The disk format keeps unchanged.
Qcow2—The disk format is qcow2.