Help Center/ Server Migration Service/ FAQs/ Target Server Configuration and Launch/ What Are the Differences Between Target and Source Servers After the Migration?
Updated on 2024-08-15 GMT+08:00
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What Are the Differences Between Target and Source Servers After the Migration?

The target server settings such as OS, OS files, and parameters you configure when you create a migration task are applied on the target server. So there are some differences between the source and target servers. They are listed in the following tables (for reference purposes only and with the final interpretation by SMS). In addition, the target server settings will change with system updates after the migration.

Table 1 Items that are not changed (applicable to both Windows and Linux)

Item

After Migration

Remarks

OS type

The target server runs the same type of OS as the source server.

The original OS of the target server is overwritten.

IP address

The IP addresses of the target server are used.

The target server uses its original public IP address. If the private IP address of the source server is included in the network segment of the VPC to which the target server belongs, the private IP address can remain unchanged.

Username

The target server uses the same username as the source server.

None

Password/Certificate

The target server uses the same username, certificate, and password as the source server.

None

Data

The target server has the same data, including files, applications, and configurations, as the source server.

None
Table 2 Items that are changed - Windows

Item

After Migration

Remarks

Host name

The host name may be changed.

Services associated with the host name may be affected.

MAC address

The MAC address of the target server is used.

A MAC address is a unique identifier assigned to a NIC when a target server is created.

DNS

The DNS settings are probably changed on the target server.

  • The DNS configuration files on the target server are the same as those on the source server.
  • The DNS settings of the subnet that the target server belongs to affect the DNS resolution of the target server.

After the migration is complete, you can modify the DNS settings of the target server.

EIP

The EIP bound to the target server is used.

None

Disk and partition sizes

The disk and partition settings from the source server are retained on the target server.

If you choose to resize disks and partitions for the target server when you configure the migration task, the new disk and partition settings are applied on the target server.

Security Identifier (SID)

The SID of the target server is used.

In Windows, a SID is a unique, immutable identifier for a server in a given domain. If the source server is added to a domain, the SID will become invalid on the target server. You need to add the target server to the domain again.

Registry and BCD files

The registry and BCD file are modified as needed.

SMS modifies the registry and BCD files to adapt the target server to Huawei Cloud.

Dynamic partitioning

The dynamic partitioning settings are modified.

This is for Windows servers that boot from BIOS.

Driver file directory

The source driver files are replicated to the driver directory on the target server.

None
Table 3 Items that are changed - Linux

Item

After Migration

Remarks

Host name

The host name may be changed.

Services associated with the host name may be affected.

MAC address

The MAC address of the target server is used.

A MAC address is a unique identifier assigned to a NIC when a target server is created.

DNS

The DNS settings are probably changed on the target server.

  • The DNS configuration files on the target server are the same as those on the source server.
  • The DNS settings of the subnet that the target server belongs to affect the DNS resolution of the target server.

After the migration is complete, you can modify the DNS settings of the target server.

EIP

The EIP bound to the target server is used.

None

Disk and partition sizes

The disk and partition settings from the source server are retained on the target server.

If you choose to resize disks and partitions for the target server when you configure the migration task, the new disk and partition settings are applied on the target server.

Disk name

New disk names are generated based on the virtualization type of the target server.

Services are not affected.

UUIDs and PARTUUIDs of disks and partitions

New UUIDs and PARTUUIDs are generated on the target server.

This only applies to Linux file-level migrations.

GRUB configuration files

GRUB configuration files are modified based on the boot disk or boot partition UUID on the target server.
  • GRUB needs to be installed on target servers that boot from the BIOS. SMS modifies the GRUB configuration files in the /boot/grub directory of every target server.
  • For target servers that boot from UEFI, SMS modifies UUID in the GRUB configuration files located in the /boot/efi/ and /boot/grub directories.

initrd or initramfs for startup

SMS injects related drivers into the initrd or initramfs file.

This is to ensure that the target server can start properly on Huawei Cloud.

X11 configuration file xorg.conf

Configuration file /etc/X11/xorg.conf is modified on the target server.

This file stores the GUI and display settings. The original file is backed up as /etc/X11/xorg.conf.bak.

Third-party tools

The following tools are deleted from the target server:

  • /etc/rc.d/rc5.d/vmware-tools
  • /etc/rc.d/rc3.d/vmware-tools
  • /etc/init.d/vmware-tools

None

SELinux security configurations

A new /.autorelabel file is generated to relabel all file systems.

This only applies to Red Hat, CentOS, and Oracle Linux distributions.

Password reset plug-in

Password reset plug-in CloudRestPwdAgent is installed in the /home directory on the target server.

If you do not want to install this plug-in, change the value of installPwdAgent in the g-property.cfg configuration file to false before the migration.

System time

NTP configuration file /etc/ntp.conf is modified on the target server.

The system time is changed to the standard time of the region where the target server is located.

MOTD

The /etc/motd file is cleared on the target server.

By default, no startup screen message is set on the target server.

fstab startup items

A new fstab file is generated based on the UUIDs and mounting statuses of partitions on the target server.

Startup records in the original /etc/fstab file are commented out on the target server.

Cloud-Init

Cloud-Init is disabled on the target server.

The /etc/cloud/cloud.cfg file is deleted.

NIC settings

SMS deletes some network-related configuration files from the /etc/udev/rules.d/ directory, and backs up and modifies DHCP configuration files based on the target server OS.

The NIC configuration file varies with OS.

For example:

  • ifcfg-ethx: Red Hat, CentOS, SUSE, and EulerOS
  • Yaml file: Debian and Ubuntu

Google services

Services on the source platform, such as Google services, are disabled on the target server by default.

Services from source platforms cannot run on Huawei Cloud. If these services are not disabled, the target server may fail to start or the services may be abnormal.

You can run the following command on the source server to check whether there are Google-related strings in the automatic startup program:

(find /etc/systemd/system/ -name 'google*' -type l | grep 'service') & (find  /etc/init/  -name 'google*' | grep 'conf') 2>/dev/null