Constraints

This section describes constraints on using MgC.

**Table 1** Restrictions on using MgC
Item	Constraint
Server migration workflows	Each server can be migrated by only one workflow. Server migration workflows cannot migrate servers that boot using UEFI and have no targets associated. To migrate such servers using a workflow, associate them with existing UEFI servers on Huawei Cloud in advance. You can also use the Server Migration Service (SMS) to migrate such servers. SMS constraints also apply to server migration workflows. To migrate a server again, you need to stop the workflow, stop the SMS-Agent process on the server, delete the server record from the SMS console, and create a new workflow.
Resource assessment and recommendations	Target servers must have disks as least as large as source servers. Target servers must have the same type of OS as source servers. There must be a sufficient quota of recommended disk types in the target region.
Migration prerequisite	All servers have been assessed or associated with target servers.
Precautions during migration	After a migration workflow is created, the source servers must not be stopped or restarted, and disks on the source servers must not be changed. Otherwise, the migration will fail.
Source server settings	Any firewall or antivirus software must be stopped and WinRM must be started on Windows source servers. You can run winrm quickconfig check the WinRM settings.
Network connectivity	Source servers must be able to access target servers. Port 22 must be opened on Linux target servers, and ports 22, 8899, and 8900 must be opened on Windows target servers.
Servers where Edge is installed	You are advised to prepare a Windows server for installing Edge in the source environment. The Windows server must be able to access the Internet. The PowerShell version of the Windows server where the Edge is installed must be later than 4.0. You can run the $host command in the PowerShell command window to view the version.

The following table lists the constraints on cross-AZ migration using MgC.

**Table 2** Constraints on cross-AZ migration
Item	Constraint
Source server specifications	Automated installation of KVM drivers is not supported for cross-AZ migrations. You need to manually install KVM drivers on source servers that use Xen by referring to Installing KVM Drivers.
Source server quantity	A maximum of 30 servers can be migrated at a time using the automated process. A maximum of 100 servers can be migrated at a time using the manual process. Given the same set of environmental conditions, the more source servers there are being migrated, the slower the migration speed.
Source disk	Servers whose system disks are larger than 1 TB cannot be migrated. You are advised not to migrate servers whose total disk capacities exceed 4 TB.
Source server status	Frozen source servers in the retention period cannot be migrated.
Target server	Migrating to existing target servers is not supported. Target servers created by MgC are billed on a pay-per-use basis. You can manually change their billing mode from pay-per-use to yearly/monthly after the migration is complete.
Shared file systems	MgC cannot migrate files from shared file systems such as NFS or CIFS, or from NAS devices.
Applications bound to hardware	MgC cannot migrate OSs that contain applications bound to hardware.
Servers added to a domain	After migrating servers added to a domain, you need to add them to the domain again.
Encrypted files	MgC cannot migrate OSs that contain protected folders or encrypted volumes.
External storage of servers	MgC cannot migrate data from the external storage attached to a source server.
Server passwords	Passwords of Linux servers remain unchanged before and after the migration. Passwords of Windows servers may change after the migration. For details, see What Are the Precautions for Performing a Cross-AZ Migration?