Help Center/ Migration Center/ FAQs/ Storage Migration/ What Are the Restrictions on Using MgC for Storage Migration?
Updated on 2024-09-05 GMT+08:00
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What Are the Restrictions on Using MgC for Storage Migration?

The following table lists the constraints on storage migration using MgC.

Item

Constraint

Objects with multiple versions

By default, only the latest version of objects in source buckets is migrated.

Storage class of target buckets

The storage class of target buckets can only be Standard or Infrequent Access. You can change the storage class of target buckets after the migration is complete.

Migration object
  • An object name cannot contain special characters.
  • A single object cannot be larger than 4.76837158203125 TB (500 MB x 10,000). Otherwise, the migration may fail.

Migration network

Migrations over private and public networks are supported.

Symbolic links
  • MgC cannot migrate files using soft links. If you need to migrate a path pointed to by a soft link, you need to:
    • Enter the actual path to be migrated when creating a migration workflow.
    • After the migration is complete, manually create a soft link to the path at the target.
  • For data sources of the NAS_SMB type, files cannot be migrated using soft links.
  • During the migration from Alibaba Cloud OSS or NAS_NFS, if there are soft links at the source, enable Migrate Metadata when creating a migration workflow. Otherwise, the soft links become regular files after migration, losing their link functionality.

Migration scope

You can migrate a single bucket or multiple buckets in batches.

Metadata migration

Metadata migration is not supported for heterogeneous migrations.

Archived data

To migrate archived data from object storage, you must restore it first. You need to:

  • Create migration workflows after the restoration is complete.
  • Configure a validity period for restored data based on the total amount of data to be migrated. This helps prevent migration failures because restored data becomes archived again during the migration.
  • Pay your source cloud vendor for restoring archived data. To learn about the pricing details, contact your source cloud vendor.

Concurrent subtasks

You can define the number of concurrent subtasks based on the number of online migration nodes. There cannot be more than 10 concurrent subtasks for each online migration node.

For example, if there are 2 online migration nodes, the maximum number of subtasks can be 20 or any number below.

Object list files

These files must be stored in the same region as the target bucket.

  • The files must be in .txt format, and their metadata Content-Type must be text/plain.
  • A single file can contain a maximum of 100,000 rows.
  • A single file cannot exceed 300 MB.
  • A maximum of 10,000 list files can be stored in the folder.
  • The files must be in UTF-8 without BOM.
  • The length of each line in a file cannot exceed 65,535 characters, or the migration will fail.
  • The Content-Encoding metadata of the files must be left empty, or the migration will fail.
  • In the files, a tab character (\t) must be used to separate the URL and new file name in each line. The format is [URL][Tab character][New file name]. Only the Chinese and special characters in the names must be URL encoded.
  • Spaces are not allowed in each line in a file. Spaces may cause migration failures because they may be mistakenly identified as object names.
Parent topic: Storage Migration