Data Online Migration:Common causes of a migration failure and solutions

BOS enables traffic throttling on source data addresses due to a large number of requests.

The last modification time of files at the source data address is later than the last modification time of files at the destination data address. A file verification error occurs if you update source files after these files have been migrated to the destination bucket.

Migrate the updated source files.

A connection that is used to send or receive data is closed by OSS. If the interval between two uploads exceeds 1 minute, the connection that is used to upload data is closed by OSS. Generally, the error is caused by network issues such as high network latency.

Retry the migration job.

The source and destination data addresses have files with the same name. The last modification time of the file at the destination data address is later than the last modification time of the file at the source data address. The file is ignored during the migration. However, an error may occur when the system checks the file after the migration job is complete.

• If you need to migrate the file, you can retry the migration after you delete the file at the destination data address or modify the file name.
• If you do not need to migrate the file, you can ignore the error.

Permissions are insufficient. When you create data addresses, you must use an account that has the read permissions on the source data address and the write permissions on the destination data address. After a migration job is started, an error occurs if you modify the permissions of the account or the access permissions of OSS buckets, such as modifying the policies for OSS buckets.

Retry the migration after you restore the permissions of the account.

Data Online Migration does not allow you to migrate objects whose storage class is Archive in OSS. The error occurs when the source contains such objects.

• If you need to migrate objects whose storage class is Archive, retry the migration after you change the storage class to Standard.
• If you do not need to migrate these objects, ignore this error.

The HTTP header or user metadata of a file contains special characters that cannot be identified during the migration.

• Retry the migration after you modify the HTTP header or user metadata of the file.
• Manually migrate the file that fails to be migrated.

When you migrate data from Apsara File Storage NAS (NAS) to OSS, the migration job enters the Invalid state. After you move the pointer over the icon, the following error message is displayed: It is timeout to check the data source, please make sure all the parameters are correct and retry later.

The IP address of the elastic network interface (ENI) used for migration cannot access the NAS file system in the virtual private cloud (VPC).

Check whether access control or security groups are configured for the NAS file system. IP addresses used for migration are dynamic and random. You must authorize all IP addresses in the VPC to access the NAS file system.

The error message indicates that the current connection is not secure.

We recommend that you use an endpoint with HTTPS connections.

When you migrate data between OSS buckets, the UserDisable error message is displayed for the files that fail to be migrated.

Your account is disabled due to multiple possible reasons. For example, OSS is not activated for your account, or your account has overdue payments or security risks. In these cases, the UserDisable error occurs.

Check whether OSS is activated for the account used to access the source and destination buckets and whether the account has overdue payments. You can also contact Alibaba Cloud OSS technical support to check whether the account is disabled.

When you create a NAS data address, the data address enters the Invalid state. After you move the pointer over the icon, the following error message is displayed: mgw.service.agent.sAddrPrefixInvalid.

The prefix of the data address is invalid or no file is found at the data address.

• Check whether the specified prefix is valid.
• Make sure that at least one file is stored at the data address.

When you migrate NAS files, the amount of data at the source data address is 5.8 TB, whereas the amount of data migrated to the destination data address is 11 TB. The amounts of data at the source and destination data addresses greatly differ.

If symbolic links are found at the source data address, the files or directories to which the symbolic links point are migrated to the destination data address. However, the symbolic links are not migrated. This way, the actual amount of migrated data is larger than the estimated amount, and the migration progress is beyond 100%. The actual amount of migrated data prevails.

Check whether the source contains symbolic links. If so, we recommend that you pause the migration job, process the symbolic links, and then create another migration job.

When you create a NAS data address, the data address remains in the Creating state for more than half an hour.

An error occurs when resources are allocated.

We recommend that you delete the data address and create a data address again.

When you create a NAS data address, the data address enters the Abnormal state. After you move the pointer over the icon, the following error message is displayed: mgw.service.agent.dMountNasFailed.

• Check whether access control or security groups are configured for the NAS file system. IP addresses used for migration are dynamic and random. You must authorize all IP addresses in the VPC to access the NAS file system.
• Check whether the prefix of the data address is valid and whether the path of the shared folder is the same as the subdirectory that you specify for the data address.
• Check whether the shared folder on the ECS instance is available and whether the NFS service is enabled.

When you migrate data from an OSS bucket in the China (Shenzhen) region to an OSS bucket in the China (Hong Kong) region, the migration job enters the Failed state.

The network connection between regions in the Chinese mainland and the China (Hong Kong) region is unstable. An error occurs when the network connection times out.

Create a migration job again in another time period.