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Before You Start

There are some constraints imposed on DRS to improve the stability and security of data migration. Before migrating data, ensure that all storage engines meet the requirements.

Before Backing Up File

Learn the backup migration constraints before starting a migration task.

Table 1 Before backing up file

Scenario

Preparations

OBS bucket
  • An OBS bucket is available. If there is no OBS bucket, create one. For detailed operations, see Creating a Bucket in the Object Storage Service Console Operation Guide.
  • Database backup files have been uploaded to the OBS bucket. If there are no backup files in the OBS bucket, upload local backup files to it and ensure that the backup file name format is correct. For details about how to upload backup files, see the Uploading a File section in the Object Storage Service Console Operation Guide.
  • OBS Browser has been installed for uploading multiple files in batches or large files greater than 50 MB in size. For detailed operations, see the Introduction to OBS Browser.
NOTE:
  • Currently, KMS encryption is not available when you upload backup files to an OBS bucket.
  • When you upload backup files to an OBS bucket, select Standard for Storage Class. Otherwise, the migration will fail.
  • You are advised to store backup files in independent OBS buckets in the same region as the destination DB instance.

RDS full backup files

The source Microsoft SQL Server DB instance has full backups. If there are no full backups, create a full backup for the DB instance. For details, see the Creating a Manual Backup section in the Relational Database Service User Guide.

Constraints

This section describes constraints on backup migrations of Microsoft SQL Server databases.

  • DRS has the following constraints on common operations in the case of migration failures caused by unpredictable errors or sudden environment changes:
    Table 2 Operation constraints

    Type

    Operation Constraints

    Notes
    • Requirements in Table 3 apply to the entire migration process.
    • The OBS bucket and DB instance must be in the same region.
    • The available disk space of the destination database is at least 1.5 times the total data size of the backup database.
    • Backup database name is case-sensitive and must be the same as the database name in the backup file.
    • The database backup file from a database of later version cannot be restored on the instance database of an earlier version (for example, restored from version 2017 to 2016).
    • The restoration from Enterprise Edition to Standard Edition to Web Edition may fail. That depends on whether the features of the later version are enabled.

    Precautions
    • During a migration, if Overwrite Data is set to Yes, high availability of the destination database is disabled by default. After the migration is complete, high availability is restored automatically.
    • During a migration, stop writing transactions to the destination database.
    • If a primary/standby switchover of the destination database is performed, the backup migration fails. In this case, the migration task cannot be restored.
  • DRS automatically checks the configurations and provides handling suggestions. Ensure that the environment configuration meets the following requirements.
    Table 3 Environment constraints

    Type

    Usage Constraints (DRS Automatic Check)

    Database permissions

    Before creating a backup migration task, ensure that the current account has the OBS and bucket permissions.

    Backup database names
    • Backup database names are case-insensitive, must be unique, and cannot be any of the following:
      • msdb
      • master
      • model
      • tempdb
      • rdsadmin
      • resource
    • The name of the OBS bucket contains 1 to 256 characters, including letters, digits, underscores (_), and hyphens (-).

    New database name
    • The new database name must be unique and cannot be any of the following (case-insensitive):
      • msdb
      • master
      • model
      • tempdb
      • rdsadmin
      • resource
    • The new database name contains 1 to 128 characters, including letters, digits, underscores (_), and hyphens (-).

    Local backup files
    • The suffix of the backup file to be uploaded to an OBS bucket must be .bak. Only .bak files can be selected in the OBS backup file list.
    • The backup file name contains 1 to 200 characters.
    • The backup file name can contain only uppercase letters, lowercase letters, digits, hyphens (-), and underscores (_).
    • Backup files are classified into full backup files and log backup files.

    Backup file sources
    • OBS buckets: store local backup files in its root directory.
    • RDS full backups: Backup files are manually or automatically created for RDS DB instances.
Parent topic: Backup Migration