USMC

Concept

What is USMC?

USMC (SCloud Server Migration Center) is a product designed to assist users in migrating physical servers, virtual machines, and cloud hosts from other cloud service providers or IDC (Internet Data Centers) to SCloud’s public cloud.

Product Advantages

Simple and Easy to Use

• The USMC client is lightweight and requires no installation.
• Supports configuration of filtering rules, excluding files/directories on Linux and drive letters on Windows.
• Provides one-click script execution.

Zero Downtime Migration

• On the source machine, USMC only performs read and copy operations, allowing the customer’s business to continue running normally during migration.

Resume from Breakpoints

• During migration, users can pause or resume transmission at any time via the console.
• If network fluctuations cause the agent to go offline, the transfer progress can be restored after restarting the agent.

Incremental Migration

• Supports incremental migration tasks. After the initial full migration is completed, periodic incremental updates ensure a smooth business transition.

MAC/IP Retention

• The target host’s MAC address can remain unchanged (via API), preventing the invalidation of certain software licenses.
• The target host’s internal IP can remain unchanged (by pre-creating a VPC), avoiding the need for business network reconfiguration.

High Security

• Data transmission uses RSA asymmetric encryption.
• Supports transmission via internal networks or dedicated lines.

Supported Scenarios

Source and Destination

USMC currently only supports migration to SCloud public cloud UHost and does not support migration to SCloud physical cloud or lightweight cloud instances.

Choosing the appropriate task plan type will improve the migration experience. However, OS adaptation for specific cloud providers may take time. If a specific cloud provider is not supported, selecting “IDC” may be an alternative. See the next section for details.

Supported Operating Systems

USMC currently supports x86_64 systems only and does not support 32-bit or ARM-based systems.

Linux

Windows

Supported Regions

USMC supports a total of 22 regions, including 6 in China, 8 in Asia-Pacific, 3 in the Americas, and 5 in Europe, Africa, and the Middle East.

USMC depends on cloud disk services. If a specific availability zone runs out of disk capacity or is not enabled, migration will not be possible.

Constraints and Limitations

• Disk Size Limits: The system disk should be ≤1000GB, and data disks should be ≤8000GB, with at least 500MB of available space. (For Linux exceeding these limits, please contact technical support.)
• No In-Memory Data Migration: USMC does not migrate memory data, so products like Redis or other in-memory databases cannot be migrated.
• Database Migration Considerations: If the machine contains MySQL, PostgreSQL, MongoDB, or TiDB services, it is recommended to use UDTS to migrate the database first or stop the service/business before migration.
• Hostname Not Migrated: USMC does not migrate hostnames. If the machine runs services that depend on the hostname, such as RabbitMQ or Kubernetes (K8S), please handle them manually.
• RAID & LVM Not Supported: Linux machines with RAID disk arrays or LVM volumes are not supported for migration.
• Shared File Systems: If the machine contains a shared file system such as NFS or NAS, it is recommended to unmount them before starting migration.
• Linux Read Permission Requirements: Ensure the directories have sufficient read permissions, and preferably run the agent as the root user.
• Possible MAC/IP/SID Changes: After migration, the server’s MAC, IP, or SID may change, which could cause application license invalidation. Users must resolve this issue themselves.

Billing Information

The USMC product itself is free of charge. However, during the migration process, a temporary intermediate instance is created under the user’s account to facilitate migration. The costs associated with this instance are borne by the user.

• UHost: The intermediate instance is a Fast UHost VM with the same configuration as the source machine. It runs continuously during migration and is charged based on CPU/Memory usage. Once the migration is complete, the instance is automatically reinstalled to become the target machine.
• UDisk: USMC provisions the necessary disks based on the source machine’s information and mounts them to the intermediate instance for data transfer. These disks are charged based on storage capacity.
• EIP: If the migration is performed over the public internet, the intermediate instance will be assigned an Elastic IP (EIP). Users can choose between bandwidth-based or data transfer-based billing. Once the migration is complete, the EIP can be unbound and released if no longer needed.

Frequently Asked Questions

How to exclude files during Linux migration?

Before executing go2SCloud.sh, add the following line to agent_config.conf:

excludeRulesFile=”/root/myRules.txt”

The myRules.txt file contains exclusion rules, formatted as follows:

How to exclude drive letters (e.g., D and F) in Windows migration?

Before executing go2SCloud.bat, add the following line to agent_config.conf:

winExclude=“D,F”

Note: Multiple partitions on the same disk are not supported.

Can USMC migrate GPU machines?

Yes, but the console does not provide a direct option. Users must use the API to create migration tasks manually.

Note: SCloud requires a specific CPU/Memory-to-GPU ratio. If you are unfamiliar with this, please contact technical support.

What factors affect the migration speed?

The actual transfer speed is primarily determined by:

1. Source machine’s outbound bandwidth (your server).
2. Target machine’s inbound bandwidth (Step 3 - Host Configuration).
3. Bandwidth limits set in Step 3 - Migration Configuration (the smallest of these values will be the bottleneck).

Other influencing factors:

• Linux Migration: Uses file-based transfer. The actual occupied space and the presence of many small files can slow down migration.
• Windows Migration: Uses block-based transfer. The transfer speed is proportional to the actual occupied disk space, provided the disk is not fragmented.
• Cross-region migrations (e.g., migrating from Alibaba Cloud Hangzhou to SCloud Hong Kong) may be significantly slower due to network latency and instability.

If migration is taking too long, consider improving network quality.

Can USMC retain the MAC address?

Yes, but this feature is not enabled in the console. Users can either call the API or request technical support.

I want to migrate my machine to Moscow, but the API specified an O-type machine, and the actual target became N-type. Why?

The Moscow region does not support O-type instances and also does not support security groups.

The Supported Scenarios page lists Ubuntu 22 as supported, but without Alibaba Cloud adaptation. Can I still migrate?

Yes, you can select IDC as the migration source when creating the migration task.

USMC optimizes widely used third-party cloud systems (e.g., removing Alibaba Cloud monitoring agents) to enhance the migration experience.

If your cloud provider is not listed, try creating a migration source as IDC. If issues arise, contact technical support.

For Windows, you can select any migration source.

The Supported Scenarios page does not list Debian 12. Can I still migrate?

No, Debian 12 is not supported. You may contact technical support to request future support.

Can I migrate consumer editions of Windows (e.g., Windows 7/8/10)?

Currently, consumer Windows versions are not officially supported. You may contact technical support.

After starting the migration script, the agent does not appear online in the console. What should I do?

First, try refreshing the page. If the agent still does not appear, follow the Migration Guide to check network requirements.

After migration, I cannot log in with the password set during task creation. What should I do?

This is usually caused by security policies in the source OS (e.g., Windows blocking bat or ps1 scripts).

Try logging in using the original source machine password or contact technical support.

My source machine was CentOS 7.8, but the console shows CentOS 8.4. Why?

Your migration task is not yet complete. The intermediate machine uses CentOS 8 by default. After completion, it will be replaced with the target machine.

USMC uses fixed intermediate images: CentOS 8 for Linux and Windows Server 2019 for Windows.

After starting the migration task, the progress remains at 0% for a long time. What should I check?

Ensure that the firewall/security group allows port 22.

After migration, I rebooted and found a new kernel. Can I switch back to the old one?

For better compatibility, USMC installs a SCloud-customized Linux 4.19 kernel.

Switching to the old kernel may cause boot failures.

My migration progress has been stuck at 67% for a long time. Why?

Check the task details to see if auto-incremental migration is enabled. If the incremental interval is very small, the console will keep showing progress at 67%.

The console does not support disabling auto-incremental migration. Please contact technical support to disable it.