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    Server Migration Center:Migrate servers to Elastic Compute Service (ECS)

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    Server Migration Center:Migrate servers to Elastic Compute Service (ECS)

    Last Updated:Dec 05, 2025

    Server Migration Center (SMC) helps you securely and efficiently migrate servers to Alibaba Cloud Elastic Compute Service (ECS). You can migrate servers from on-premises data centers, virtual machines (VMs) such as VMware, VirtualBox, Xen, KVM, and Hyper-V, and other cloud platforms such as Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform (GCP), Tencent Cloud, UCloud, China Telecom Cloud, and QingCloud. SMC simplifies the migration process and greatly reduces the technical barriers and risks of server migration.

    Migration scenarios

    Important

    Due to a change in the intermediate technology solution for server migration, Server Migration Center (SMC) will no longer support migrating Windows servers to destination instances in Alibaba Cloud regions outside the Chinese mainland after 11:59 PM (UTC+8) on November 30, 2025. Before this date, SMC client V2.8.5 and earlier can still be used. For more information about the change and its impact, see Notice on SMC Discontinuing Support for Migrating Windows Servers to Destination Instances in Regions Outside the Chinese mainland.

    • (Recommended) Migrate a server to an Alibaba Cloud ECS custom image.

      If you have not purchased an Alibaba Cloud ECS instance, you can migrate your server to an Alibaba Cloud ECS custom image. Then, you can use the custom image to manually create an ECS instance.

    • Migrate a server to an existing Alibaba Cloud ECS instance.

      If you have already purchased an Alibaba Cloud ECS instance and its storage, operating system, and other configurations are compatible with the source server, you can migrate the source server to the existing ECS instance.

      Warning

      After migration, the original data on the destination ECS instance is erased. The data on the source server is not affected. Therefore, do not use this method if the destination ECS instance contains important data.

    Migration impact

    Before you migrate, consider the following impacts.

    Impact

    Description

    Migrated data directories

    During migration, SMC automatically generates a disk partition structure for the destination that is as consistent as possible with the source server's disk partition structure. You can adjust the partition structure of the destination disk, including partition size, order, transfer method, and LVM configurations.

    By default, all disks on the server are migrated:

    • If a data disk has no mount target, the data disk is not migrated.

    • If you do not need to migrate certain partition directories, you can choose not to migrate them when you adjust the partition structure.

    Intermediate instance

    Do not interfere with the intermediate instance.

    To prevent migration failure, do not stop, start, restart, or release the intermediate instance, or change its billing method during the migration. After the migration is complete, the intermediate instance is automatically released.

    Note

    • During each migration, SMC creates a temporary pay-as-you-go intermediate instance named No_Delete_SMC_Transition_Instance in your destination Alibaba Cloud account to assist with the migration.

    • If you choose to migrate to a destination instance, that instance serves as the intermediate instance and is not automatically released.

    For more information, see Migration principles.

    IP address

    The IP address changes after migration, which may cause service interruptions. We recommend that you perform the migration during off-peak hours. If your services involve IP address configurations, modify the domain name resolution and ICP filing information yourself after the migration.

    Underlying hardware devices

    The underlying hardware devices change after migration. This may invalidate some application licenses that are bound to hardware. Check your licenses.

    Performance impact

    The migration process consumes server resources, including CPU, memory, disk I/O, and network bandwidth.

    Data consistency before and after migration

    For information about data and system configuration changes that occur before and after migration, see Data consistency issues after migration.

    Impact on related web applications after server migration

    After you migrate a server to Alibaba Cloud ECS, several aspects of your environment change, including network topology, computing and storage resources, application security settings, costs, monitoring, compatibility, network latency and bandwidth, and backup, recovery, and O&M processes. You must also consider the following aspects:

    Impact

    Description

    Network connectivity

    After the server migration, the ECS instance will use a new virtual private cloud (VPC). Its network location and other configurations will change with the VPC migration. This ECS instance cannot directly communicate with the original network or other ECS instances in the VPC. To enable cross-account and cross-VPC communication, see VPC interconnection.

    Security group

    After the server migration, the ECS instance will use new security group rules to control inbound and outbound traffic. Changes in access rules may affect normal business access. If the destination account's security group does not have corresponding security group rules, you can quickly add them by exporting the rules from the security group associated with the original ECS instance and importing them into the destination security group. For more information, see Import and export security group rules.

    SSL Certificate

    If your website uses HTTPS, you need to apply for and install an SSL Certificate. You can apply for a free SSL Certificate from Alibaba Cloud. Deploy the SSL Certificate to the ECS instance. For more information, see Purchase and deploy an SSL certificate to an ECS instance.

    Data migration

    To migrate data from other servers to Alibaba Cloud, you can use methods such as FTP, SCP, or manual backup to OSS. For more information, see Transfer files to an ECS instance and Use ossutil to transfer data to an ECS instance.

    Other configurations

    Ensure that database connections, APIs, Server Load Balancer (SLB), and other settings point to the new domain name and ECS IP address.

    Preparations

    • Complete the pre-migration preparations for the server.

    • Read the migration guide to understand the SMC client, migration principles, billing, migration process, and feedback channels.

    • To prevent data loss, back up important data to an image, snapshot, or a storage device other than the instance before migration.

    • To migrate a server across international regions, the migration may be slow because of unstable public network conditions. Estimate the migration time and test the transfer speed. We recommend that you connect the source server to an Alibaba Cloud VPC using a VPN Gateway, Express Connect circuit, or Smart Access Gateway to migrate over a private network.

    • If you can directly access a VPC in an Alibaba Cloud region from your on-premises data center, VM environment, or cloud host, we recommend that you use the SMC private network migration solution. This solution is faster and more stable than using the public network and can improve migration efficiency.

    • To migrate the source server to an existing Alibaba Cloud ECS instance:

      • If the source server runs Linux, the destination instance must also run Linux. If the source server runs Windows, the destination instance must be a Windows server.

      • The number of data disks attached to the destination instance must be greater than or equal to the number of data disks on the source server. If the destination instance does not have enough data disks, you must attach data disks.

      • The capacity of the system disk and data disks on the destination instance must be greater than or equal to the capacity of the corresponding disks on the source server. If you plan to reduce the disk size during migration, the disk capacity on the destination instance must be greater than or equal to the used disk space on the source server. If the disk capacity of the destination instance is insufficient, you must resize the disks.

    Migration procedure

    Step 1: Import the migration source

    A migration source is the data center server, VM, or cloud host from another platform that you plan to migrate.

    Import the migration source with a single command (Recommended)

    Important

    • The source server must have public network access. If the source server has firewall restrictions, see What are the service domains of SMC? to obtain the SMC domain names and ports, and add them to the firewall whitelist.

    • If your source server cannot access the public network or you want to improve migration efficiency by transferring data over a private network, see the private network migration solution.

    1. Go to SMC console - Server Migration.

    2. On the Server Migration page, click Import Migration source.

    3. Configure the parameters as prompted on the page and copy the activation code command. The parameters are described in the following table.

      Parameter

      Description

      Workgroup (Optional)

      This applies to the scenario of batch migration to cloud server images. For single server migration, skip this parameter.

      You can add multiple migration sources to the same workgroup for management. Migration sources associated with a workgroup must have automatic incremental synchronization enabled during migration. For more information about batch server migration, see Batch server migration.

      If no workgroup has been created, click Create a New Workgroup.

      Migration Source Type

      Physical servers/VMs/Cloud servers of other cloud platforms

      Import Method

      Select Use CLI To Import Server.

      Generate an activation code script command as needed. Run the command on the source server with a single click to import the migration source.

      Migration Source Quota

      The number of migration sources that can be activated by the activation code. The value ranges from 1 to 1000. The default value is 200.

      Validity Period

      The validity period of the activation code. The value ranges from 1 to 90 days. The default value is 90 days.

      Activation Code

      After generating the activation code, copy the command. Perform the following steps:

      1. Click Generate.

      2. Based on the source server's operating system, click the Linux Shell or Windows Powershell tab.

      3. Click Copy to copy the activation code command.

    4. Log on to the source server, and then paste and run the copied command with administrator privileges to import the migration source.

      Linux source server

      1. Log on to the Linux source server.

      2. Paste and run the copied command with administrator privileges to import the migration source.

        image.png

        After you run the command, a message similar to Import Source Server [s-bp18x8751kgz2oyh****] Successfully! appears, which indicates that the migration source was imported successfully.

      Windows source server

      1. Log on to the Windows source server.

      2. Open Windows PowerShell with administrator privileges.

      3. Paste and run the copied command to import the migration source.

        image.png

        After you run the command, a message similar to Import Source Server [s-bp19rlidl3mwuptc****] Successfully! appears, which indicates that the migration source was imported successfully.

        If the command fails to run, see What do I do if the command fails to run when I import a Windows migration source from the command line?.

    5. On the Server Migration page in the SMC console, check the status of the migration source in the Real-time Migration Status column.

      • A status of Migration SourceOnline indicates a successful import.

      • If the status is not Source Online, the import failed. Troubleshoot the issue using the following methods and then re-import the source.

        • Troubleshoot the issue based on the error message in the console or by checking the SMC client log file. The default installation directories for the SMC client are:

          • Windows source server: C:\smc.

          • Linux source server: /smc.

        • For common issues and solutions, see SMC FAQ and Troubleshooting.

    Import the migration source using the SMC client

    Important

    • The client must be run on the source server. By default, public network access is required. If the source server has firewall restrictions, see What are the service domains of SMC? to obtain the SMC domain names and ports, and add them to the firewall whitelist.

    • If your source server cannot access the public network or you want to improve migration efficiency by transferring data over a private network, see the private network migration solution.

    1. Go to SMC console - Server Migration.

    2. On the Server Migration page, click Import Migration source.

    3. On the Import Migration source page, configure the parameters as specified in the following table.

      Parameter

      Description

      Migration Source Type

      Physical servsers/VMs/Cloud Servers of other platforms.

      Import Method

      Select Use Client to Import Server.

      You need to manually download and install the SMC client on the source server.

      Description

      1. In the Description section, follow the prompts to download, install, and activate the corresponding SMC client based on the source server's operating system (Linux or Windows) and architecture (32-bit or 64-bit).

      2. Click Generate and copy the activation code information.

        You need to enter the activation code when installing the client.

    4. Import the migration source.

      Important

      Do not close the SMC client during the migration. Otherwise, the migration source will lose its connection to the SMC console and the migration will fail.

      Import a migration source from a Windows source server

      1. Use a remote connection tool that supports file transfer, such as WinSCP, to upload the SMC client to the Windows source server.

      2. On the Windows source server, use the system's built-in or a third-party decompression tool to unzip the SMC client package.

      3. In the SMC client folder that matches the system version of your source server, run the SMC client.

        When prompted for administrator privileges, click OK.

        • GUI version: Double-click the go2aliyun_gui.exe application to run it.

        • Command-line version: Double-click the go2aliyun_client.exe application to run it.

      4. Obtain an activation code or an AccessKey pair.

        • (Recommended) Obtain an activation code. In the SMC console, go to the Description section, click Generate, and copy the activation code.

        • Obtain an AccessKey pair: An AccessKey pair for an Alibaba Cloud account includes an AccessKey ID and an AccessKey secret. If you have not created an AccessKey pair, you must create one. For more information, see Create an AccessKey pair.

      5. Enter the activation code or AccessKey pair as prompted.

        • In the GUI, enter the activation code or AccessKey pair into the Token Id/AK and Token Code/SK text boxes and click Start. For more information, see the SMC client user guide.

        • Command-line version: Enter the values for access_access_token_id and access_token_code, and press the Enter key.

        When a message similar to Import Source Server [s-bp18x8751kgz2oyh****] Successfully! appears, it indicates that the migration source was imported successfully.

      Import a migration source from a Linux source server

      1. Use a remote connection tool that supports file transfer, such as WinSCP, to upload the SMC client to the Linux source server.

      2. Remotely connect to the Linux source server and unzip the SMC client package.

        This example uses the Linux 64-bit General-purpose Edition. If you use a different version of the SMC client, replace the package name in the command with the actual downloaded file name.

        tar -zxvf go2aliyun_client.tar.gz
        Note

        The Linux 64-bit ARM Edition supports the g6r general-purpose and c6r compute-optimized instance families. For more information about instance families, see Enterprise-level Arm-based compute instance families.

      3. (Optional) As needed, filter and exclude files or directories that do not need to be migrated.

        Important

        If you enable block replication for migration, you cannot exclude files or directories from migration.

      4. Obtain an activation code or an AccessKey pair.

        • (Recommended) In the Description section of the SMC console, click Generateand copy the activation code.

        • Obtain an AccessKey pair: An AccessKey pair for an Alibaba Cloud account includes an AccessKey ID and an AccessKey secret. If you have not created an AccessKey pair, you must create one. For more information, see Create an AccessKey pair.

      5. In the SMC client folder, run the following commands to start the SMC client.

        cd go2aliyun_client_linux_x86_64
sudo chmod +x go2aliyun_client
sudo ./go2aliyun_client

      6. Enter the activation code or AccessKey pair as prompted. This example uses an activation code:adad

        After you enter the activation code or AccessKey pair, the following prompts may appear:

        • If the source system does not have a snapshot driver installed, the SMC client prompts you, as shown in the following figure. You can choose whether to install the snapshot driver based on your needs.

          • If you enable block replication when you create the migration task, enter yes to automatically install the snapshot driver.

          • If you do not enable block replication when you create the migration task, enter no.

          Important

          If the snapshot driver fails to install, do not enable block replication when you create the migration task. Otherwise, the migration will fail.

          123

        • Most mainstream source systems have rsync installed by default. If it is not installed, the SMC client prompts you. Enter yes to automatically install rsync, as shown in the following figure.安装rsync

        • If SELinux is enabled on the source system, the SMC client prompts you to disable it. Enter yes to automatically disable SELinux, as shown in the following figure.关闭SELinux

        When a message similar to Import Source Server [s-bp11npxndknsycqj****] Successfully! appears, it indicates that the migration source was imported successfully.

        Note

        If importing the migration source fails, you can troubleshoot the issue based on the displayed message, and then run the following commands in sequence to exit the background program and re-import the migration source. For more information about common issues and solutions, see SMC FAQ and Troubleshooting.

        sudo ./go2aliyun_client --abort
sudo ./go2aliyun_client

    5. On the Server Migration page in the SMC console, check the status of the migration source in the Real-time Migration Status column.

      • A status of Migration SourceOnline indicates a successful import.

      • If the status is not Source Online, the import failed. Troubleshoot the issue using the following methods and then re-import the source.

        • Troubleshoot the issue based on the error message in the console or by checking the SMC client log file. The default installation directories for the SMC client are:

          • Windows source server: C:\smc.

          • Linux source server: /smc.

        • For common issues and solutions, see SMC FAQ and Troubleshooting.

    Step 2: Configure the migration

    1. Find the migration source that you want to manage and click Start Migration in the Actions column.

    2. Configure the parameters and click Start Migration.

      1. Configure basic parameters.

        Parameter

        Description

        Destination Type (Required)

        Select a target type based on your migration scenario:

        ECS Image

        Convert the existing source server into a custom cloud server image, and then use this custom image to create a new ECS instance to complete the migration.

        The configuration items are described as follows:

        • Destination Region: The region where your source server will be migrated to in Alibaba Cloud. This parameter is required. For more information about regions, see Regions and zones.

        • Image name prefix: The name of the destination Alibaba Cloud custom image that SMC generates for the migration source.

        ECS Instance

        Migrate the source server directly to an existing ECS instance. The storage, operating system, and other configurations of the source server and the existing ECS instance must be compatible.

        Important

        When migrating to a destination instance, the operating system of the destination instance is replaced first. The automatic snapshots of the system disk are cleared and cannot be recovered. To retain automatic snapshots for future use or data security, you can manually cancel the automatic release of snapshots with the disk before migration. For more information, see Configure automatic snapshots to be released with disks.

        The configuration items are described as follows:

        • Destination Region: The region where your source server will be migrated to in Alibaba Cloud. This parameter is required. For more information about regions, see Regions and zones.

        • Destination Instance: Select an ECS instance as the destination instance.

        Migration Test

        The migration drill feature helps you fully understand the feasibility and risks of the migration task before the actual migration. It also provides information such as the amount of data to be migrated, migration speed, and total migration time, and offers repair suggestions to reduce potential problems and losses during the actual migration. Pay-as-you-go resources will incur some fees during the migration drill. By default, Migration Test is enabled.

        Warning

        If the target type is ECS Instance, snapshots will be created for all disks of the destination ECS instance during the migration drill. If the drill is abnormal or the execution method is Test Only, the snapshots will be automatically rolled back after the migration drill is completed. The destination ECS instance will be unavailable during the migration drill, and data will be lost during this period. Ensure that the destination ECS instance does not contain important data.

        For more information, see Configure a migration drill.

        Execution Method

        Select an execution method based on whether Migration Test is enabled:

        If Migration Test is enabled

        • Test Only: Creates only a migration drill task. After the migration drill is completed, to migrate the server, you must manually start the server migration task.

        • Test and Migrate: After the migration drill is completed, if there are no drill items with a status of Critical, the system automatically starts the server migration task. By default, Test and Migrate is selected.

        If Migration Test is not enabled

        • Migrate Now: Starts the migration immediately after creating the migration task. By default, Migrate Now is selected.

        • Migrate Later: After creating the migration task, it automatically starts at the set time.

          Note

          The earliest scheduled execution time can be set to 10 minutes after the current time.

        • Create Only: Creates only the migration task. You will need to manually start the migration task later by clicking Start Migration Job in the Actions column.

        Automatic Incremental Synchronization

        Whether the migration task automatically synchronizes incremental data from the source server to Alibaba Cloud. By default, automatic incremental synchronization is disabled.

        • If you enable this switch, you need to set the following configuration items:

          • Synchronization Interval: The time interval at which the incremental migration task is automatically executed periodically.

          • Maximum Reserved Images: The maximum number of images that the incremental migration task retains by default.

          The migration task will be executed periodically to synchronize incremental data to Alibaba Cloud. For best practices on incremental migration, see Incremental server migration.

        • If you disable this switch, the migration task will run only once.

        Enable a migration template

        This parameter appears only when Destination Type is set to ECS Image.

        A migration template is used to preset the parameters of a migration task. When you start the migration, the template parameters are automatically filled in. For more information about setting a migration template, see Configure a migration template.

        Network Type

        Select the network used to transfer migration data to the intermediate instance. By default, public network transfer is used. The intermediate instance will be created in the selected virtual private cloud (VPC) and vSwitch, so the intermediate instance will be assigned a public IP address.

        Public Network (Default)

        Migration data is transferred to the intermediate instance over the public network. To use this mode, the source server must be able to access the public network. Choose whether to specify a VPC and vSwitch as needed.

        • Specify VPC and vSwitch: The migration task creates an intermediate instance in the VPC and vSwitch you specify.

        • Do not specify VPC and vSwitch: The migration task creates an intermediate instance in a new VPC and vSwitch that the system automatically creates.

        VPC

        Migration data is transferred to the intermediate instance over the VPC intranet. To use this mode, you need to connect the source server to the Alibaba Cloud VPC and must specify a VPC and vSwitch.

        Note

        If you can directly access a VPC in an Alibaba Cloud region from your on-premises data center (IDC), VM environment, or cloud host, we recommend that you use this method for migration. Using intranet transfer provides faster and more stable data transfer than the public network, improving migration efficiency. You can connect the source server and the cloud VPC through a VPN Gateway, Express Connect circuit, or Smart Access Gateway. For more information, see Connect a VPC to a data center or another cloud.

        The private IPv4 address of the destination instance

        To change the private IP address of the destination instance, you can manually specify a private IP address. This parameter appears only when Destination Type is set to ECS Instance.

        • Remain unchanged: By default, the migration IP address of the Destination Instance remains unchanged.

        • Manual: Allows you to enter an address within the available IP range of the Destination Instance's vSwitch. When the migration source IP address is in the vSwitch's network segment, you can change the destination instance IP address to the migration source IP address.

          • When the destination instance network segment is the same as the migration source network segment: Directly enter the private IP address of the migration source.

          • When the destination instance network segment is different from the migration source network segment: You first need to change the VPC of the destination instance so that the destination instance network segment is the same as the migration source network segment, and then enter the private IP address of the migration source.

      2. Adjust the disk partition structure as needed. The parameters are described in the following table.

        Parameter

        Description

        Modify Disk Partition

        Choose whether to enable adjusting the disk partition structure based on your needs. This feature is supported only in SMC client V2.8.0 and later. For more information about the SMC client, see SMC client user guide.

        • Disabled: The disk information of the source instance is not displayed. The system automatically reads the source instance disk information and generates a disk structure. After migration, the destination disk partition structure is consistent with the automatically generated disk structure by default.

        • Enabled: The disk information of the source instance is displayed. The system automatically reads the source instance disk information and generates a disk structure. You can adjust the destination disk partition structure, including partition size and order, transfer method, and whether to enable LVM.

          The parameters for the disk partition structure are described as follows:

          Configure disks

          • System Disk: The size of the destination Alibaba Cloud server's system disk, in GiB. The system disk size ranges from 20 to 2048.

            The destination system disk size must be larger than the actual used size of the source system disk. For example, if the source system disk is 400 GiB and the actual used space is 100 GiB, the destination system disk size must be greater than 100 GiB.

            Note

            The default value is the size of the source system disk. If you do not need to reduce the system disk capacity, we recommend not setting it to a value smaller than the default.

          • Data Disk<N>: The size of the data disk of the Alibaba Cloud server after migration, in GiB. The data disk size ranges from 1 to 32768.

            • The variable <N> represents the data disk number. If migrating to a destination instance, N is the data disk ID.

            • The data disk size must be larger than the actual used size of the source data disk. For example, if the source data disk is 500 GiB and the actual used space is 100 GiB, the destination data disk size must be greater than 100 GiB.

            • If there is no mount target under the Data Disk or all mount targets are set not to be migrated, the data disk will not be migrated.

          • LVM: Logical Volume Manager (LVM) is a mechanism for managing disk partitions in Linux systems. LVM is more flexible than standard disk partitions and allows for dynamic adjustment of disk space.

            You can choose whether to enable LVM based on your needs. If LVM is enabled, the destination end will automatically rebuild the disk with an LVM structure.

            An example is described as follows:

            For each destination disk with LVM enabled, the system creates 1 physical volume (PV) and its corresponding volume group (VG). On this volume group, it creates a number of logical volumes (LVMs) corresponding to the number of mount targets. The volume group name defaults to vgX (where X is the disk's sequence number), and the logical volume name defaults to lvX (where X is the logical volume's sequence number), as shown in the following example:

            image

            Important

            LVM is not supported in the following cases:

            • If the migration source is a Windows system, LVM is not supported.

            • If the system disk has no boot partition, LVM is not supported.

            After enabling LVM, the feature will not take effect in the following scenarios:

            • The migration source does not support lvm2 or the lvm2 package is not installed.

            • The migration source is a Debian system with a kernel version of 3.x or earlier, and a disk with an XFS file system is mounted.

          Configure mount targets

          • Migrate: You can choose whether to migrate the mount target based on your business needs.

          • Enable Block Replication: Using block replication can effectively improve the stability of migration transfer speed and ensure consistency with the source partition structure, but the partition size cannot be modified. SMC determines whether to support enabling block replication based on the state of the migration source disk partitions.

            • If the migration source does not support enabling Block Replication for a partition, the switch cannot be turned on. The default file replication is used, and the partition size can be modified.

            • If the migration source supports enabling Block Replication for a partition, block replication is enabled by default to achieve partition-level disk migration.

            Note

            • When the migration source is a Windows operating system, the block replication feature is enabled by default and cannot be disabled.

            • If LVM is enabled on the disk and the partition size is not a multiple of 4 MiB, block replication will not take effect, and file replication will be used for data transfer.

          • Set Partition Size: When block replication is not enabled, you can set the partition size as needed, but the sum of the partition sizes cannot exceed the size of the belonging disk.

          Note

          If the disk sizes of the destination instance do not match the migration source disks, the task cannot be created. In this case, the system will automatically adjust the mount target positions to meet the disk size requirements. If the requirements are still not met after adjusting the mount targets, handle the issue according to the prompts on the page.

          You can also manually drag the mount target positions to meet the disk size requirements. However, dragging is not supported for boot or system partitions. Perform the following steps:

          1. Hover your mouse over the image icon in front of the mount target.

          2. Use the mouse to drag the mount target to another disk.

      3. (Optional) Click Advanced Settings to configure parameters such as the network mode, private IP address, and transfer throttling. For more information about these parameters, see the following table.

        Parameter

        Description

        Migration Job Name

        The name of the migration task.

        Job Description

        Enter a description for the migration task.

        Transmission Speed Limit

        Transfer throttling limits the actual network transfer speed, in Mbps. If the Compression Ratio is set to a value greater than 0, the actual network transfer speed (the transfer speed of compressed data) will be less than the speed displayed in the Real-time Migration Status.

        Compression Ratio

        The level of data compression during migration. Set the compression ratio based on your actual needs.

        • In environments with limited bandwidth, using a high compression ratio can increase data transfer speed.

        • In environments with very high bandwidth, we recommend not compressing data to reduce the consumption of CPU resources on the migration source.

        The value ranges from 0 to 10. The default value is 7. A value of 0 means no data compression.

        Checksum Verification

        Disabled by default. Enabling it enhances data consistency checks but may reduce transfer speed.

        SSL-Encrypted Transmission

        By default, Auto is selected. Using Secure Sockets Layer (SSL) encryption to transfer migration data can improve data security and ensure data integrity.

        License Type

        Select the license type.

        • Alibaba Cloud (Default): Currently only supports providing Microsoft Windows Server licenses. After migration, when creating an ECS instance from an image in Hong Kong (China) and overseas regions, a license fee for the image will be charged, and it will be automatically activated. The specific fee is subject to the information displayed when creating the instance.

        • BYOL: Bring Your Own License (BYOL) migration to the cloud currently mainly includes Microsoft, Red Hat Enterprise Linux, and SUSE Linux Enterprise Server. After migration, no image license fee will be charged when creating an ECS instance from the image. Please use your own license for activation.

          Note

          If you have already created an ECS instance, Alibaba Cloud supports quickly purchasing software licenses such as Red Hat Enterprise Linux and SUSE Linux Enterprise Server for a specified ECS instance. For more information, see Purchase a software license for an ECS instance.

        Image Check

        The image detection feature mainly checks whether the image is valid and whether it can be used to create a fully functional ECS instance. You can use the image detection feature when creating server migration and VMware agentless migration tasks.

        Image detection can help you quickly identify potential problems with the image or instance after migration and provide repair solutions to make it comply with Alibaba Cloud standards, improving the success rate of instance startup.

        For more information, see Configure image detection.

        Tag

        Bind tag key-value pairs to the migration task for easy querying and management. For more information, see Use tags to manage migration sources and tasks and Implement fine-grained permission management using tags.

        Note

        A maximum of 20 tags can be bound to a single migration task.

        Intermediate Instance Type

        You can select the intermediate instance type based on your actual needs. This parameter appears only when Destination Type is set to ECS Image.

        • After you specify this parameter, the system selects this instance type to create the intermediate instance. If this instance type is out of stock, the migration task fails to be created.

        • Do not select an intermediate instance type: The system selects instance types in a default order to create the intermediate instance.

        Important

        To avoid migration errors, do not stop, start, restart, or release the intermediate instance during the migration process. After the migration is complete, the instance is automatically released.

        Report diagnostic logs

        Automatically upload SMC client logs to the SMC server for error diagnosis and analysis, which helps in locating problems when migration errors occur. This feature is enabled by default.

        SMC client logs are generally saved in the /smc/go2aliyun_client*/Logs directory under the installation path.

    3. In the message that appears, read the migration notes and click Got It.

    4. On the Server Migration page, you can view the real-time migration status.

      If you have enabled the migration drill, SMC first performs the migration drill. The transfer time is affected by factors such as data volume and network bandwidth. Wait for the migration task to complete.

      image

      Note

      • Speed: The amount of uncompressed migration data transferred per second. For a migration task with a Compression Ratio greater than 0, the displayed speed is higher than the actual network transfer speed of the compressed data.

      • Time Remaining for Synchronization: Calculated as (Total Data Volume - Transferred Data Volume) / Speed.

      • If the transfer speed is too slow to meet your schedule, you can consider temporarily increasing the fixed bandwidth of the source and destination servers. For more information, see Estimate migration time and test transfer speed.

      You can subscribe to migration error events, modify the migration, and pause the migration.

      • To prevent the migration process from being blocked by task errors, you can subscribe to SMC migration task error event notifications in CloudMonitor to receive timely email alerts.

      • When a migration task has a status of Synchronizing, you can also perform the following operations on the task:

        • To edit the migration task, in the Actions column, click Modify Migration Job to change parameters such as transfer throttling, compression ratio, and Checksum verification.

        • To pause the migration task, click Pause Migration Job in the Actions column.

    5. (Optional) View migration details.

      In the Migration Source ID/Name column, click a migration source ID to view its details.

    Verify the migration result

    • The migration is complete when the Real-time Migration Status is Completed.

      • If you set Destination Type to ECS Image:

        After a successful migration, an Alibaba Cloud custom image is created. To view the image detection results, scroll to the right and click View Report in the Migration Deliverables column. For more information, see View image detection results.

        image

        Manually verify the migration result (Recommended)

        In the Actions column, click Create Instance. You are redirected to the instance creation page in the ECS console, where the custom image is preselected. For more information, see Create an instance from a custom image or shared image.

        image

        Automatically verify the migration result

        Note

        To use this feature, the Cloud Assistant Agent must be installed on the instance, and the instance's system version must support it. For more information, see Install the Cloud Assistant Agent.

        This feature uses the OOS template ACS-SMC-CreateAndVerifyInstance provided by Alibaba Cloud to automatically verify that the image generated by the migration task can be used to successfully create and start an ECS instance.

        1. In the Actions column, click View Migration Result.

          image

        2. In the dialog box that appears, review the verification process and click Verify Now.

          You can also click Customize Verification Parameters to manually configure verification parameters.

        3. You can view the result in the Verify Migration Result column.

          • Verified: The migration passed verification. You can click View Report to view the results.

          • Not Verified: Indicates that the migration was abnormal. You can click View Cause to view the error details and troubleshoot the issue.

          To view the execution history of the OOS template, you can also click the ... icon in the Actions column and then click View Verification Records in OOS Console.

      • If you set Destination Type to ECS Instance for the migration, you can click View Destination Instance in the Actions column to view the destination ECS instance.

      After you migrate the server, perform the following operations to ensure that your business runs normally:

    • If the migration drill status is image.png, it means the migration drill failed.

      Review the drill report, resolve the Critical drill items, and then retry the migration drill. For more information, see Configure a migration drill.

    • If the Real-time Migration Status is Error, the migration task has encountered an error.

      In this case, you need to troubleshoot the problem and retry the migration:

      1. In the Actions column, click Troubleshoot Errors. Use the error code and error message to resolve the issue. For more information, see SMC FAQ and Troubleshooting.

      2. After you resolve the issue, click Retry Migration Job in the Actions column. The migration will resume.

        Important

        If the intermediate instance has been released, you must start the migration again. For more information, see What do I do if I accidentally release the intermediate instance?.

    Clean up resources

    Migrate to a cloud server image

    During migration, SMC creates a temporary pay-as-you-go intermediate instance named No_Delete_SMC_Transition_Instance in your destination Alibaba Cloud account to facilitate the migration. You must decide whether to manually release the instance based on the migration outcome:

    • Successful migration: The intermediate instance is automatically released. You do not need to manually release it.

    • Migration error: The intermediate instance is retained for the migration task and incurs charges. You can release it in the following ways to avoid unnecessary charges:

      • To delete a migration task and automatically clean up the intermediate instance, click the migration source ID, and then click Cancel Migration Job in the Actions column for the task.

      • Manually release the intermediate instance.

    Migrate to a destination instance

    During migration, SMC creates a temporary pay-as-you-go intermediate disk named SMC_Temp_Disk and attaches it to the destination instance to facilitate the migration. You must decide whether to manually release this intermediate disk based on the migration outcome:

    • Successful migration: The intermediate disk is automatically released. You do not need to manually release it.

    • Migration error: The intermediate disk is retained for the migration task and incurs charges. You can choose one of the following ways to release it to avoid unnecessary charges:

      • If you no longer need a migration task, click the migration source ID. In the Actions column for the task, click Cancel Migration. This action deletes the task and automatically cleans up the intermediate disk.

      • Manually release the intermediate disk.

    Related documents

    • To migrate incremental data multiple times, you can perform multiple incremental migrations at custom intervals after the initial full migration is complete. This synchronizes the incremental data generated on the source server to Alibaba Cloud, which reduces business downtime and the final cutover time. For more information, see Incremental server migration.

    • For common issues and solutions, see FAQ and Troubleshooting.