您可以使用 Database Migration Service 通过备份和恢复流程将 SQL Server 数据库迁移到 Cloud SQL for SQL Server 实例。您首先将完整的数据库备份和事务日志文件上传到 Cloud Storage 存储桶。然后，Database Migration Service 会主动监控您的存储桶，并将数据持续复制到目标 Cloud SQL for SQL Server 实例。
本页面简要介绍了适用于同类 SQL Server 迁移的 Database Migration Service 关键功能：
支持的源和目标平台列出了 Database Migration Service 支持的所有 SQL Server 版本。
您可以使用 Database Migration Service 在相同的 SQL Server 版本和版本之间迁移，也可以从较低版本的 SQL Server 迁移到 Cloud SQL 支持的较高版本，前提是您遵循版本兼容性准则。如需了解详情，请参阅 Microsoft 文档，了解适用于您 SQL Server 版本的支持版本和版本升级。例如，请参阅
支持的版本和版本升级 (SQL Server 2022)。
下表列出了所有受支持的 SQL Server 源数据库和目标数据库：
源数据库
目标数据库
Amazon RDS
Cloud SQL for SQL Server 版本 2022、2019、2017
自行管理的 SQL Server
（在本地或由您完全控制的任何云端虚拟机上）
持续迁移数据流
对于从同构 SQL Server 迁移到 Cloud SQL 的情况，Database Migration Service 支持
持续迁移流程。在此方法中，系统会先从完整数据库备份文件加载数据，然后从差分备份文件加载数据，最后根据您上传到专用 Cloud Storage 存储桶的事务日志文件持续更新数据。
图 1. 使用 Database Migration Service 进行 SQL Server 迁移期间的数据移动。（点击可放大）
概括来讲，您的数据会按如下步骤完成迁移：
您将备份文件上传到 Cloud Storage。
若要进行持续的 SQL Server 迁移，您需要先对源数据库进行完整备份，然后将备份文件上传到 Cloud Storage 存储桶。对于后续更新，您可以选择提供差分备份文件，然后上传事务日志文件。您还可以自动创建和上传持续交易日志。
Database Migration Service 与
加密的 SQL Server 备份完全兼容。如果您将加密密钥上传到 Google Cloud，Database Migration Service 可以安全地解密您的数据并将其加载到 Cloud SQL for SQL Server 目标实例，而不会影响数据安全。
[[["易于理解","easyToUnderstand","thumb-up"],["解决了我的问题","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["很难理解","hardToUnderstand","thumb-down"],["信息或示例代码不正确","incorrectInformationOrSampleCode","thumb-down"],["没有我需要的信息/示例","missingTheInformationSamplesINeed","thumb-down"],["翻译问题","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["最后更新时间 (UTC)：2025-09-01。"],[[["\u003cp\u003eDatabase Migration Service allows the migration of SQL Server databases to Cloud SQL for SQL Server using a backup and restore method, where full database backups and transaction logs are uploaded to Cloud Storage.\u003c/p\u003e\n"],["\u003cp\u003eThe service supports various source databases, including Amazon RDS and self-managed SQL Servers, and can migrate between different SQL Server versions as long as version compatibility guidelines are met.\u003c/p\u003e\n"],["\u003cp\u003eData migration occurs in a continuous flow, starting with a full backup, followed by an optional differential backup, and then ongoing updates from transaction log files uploaded to a designated Cloud Storage bucket.\u003c/p\u003e\n"],["\u003cp\u003eDatabase Migration Service offers monitoring capabilities, including real-time diagnostics and detailed logs, to track the progress and health of the migration process.\u003c/p\u003e\n"],["\u003cp\u003eThe migration service can handle encrypted SQL Server backups, ensuring data security by decrypting the files using an uploaded encryption key during the migration process.\u003c/p\u003e\n"]]],[],null,["# Database Migration Service for SQL Server\n\nYou can migrate SQL Server databases to Cloud SQL for SQL Server\ninstances with Database Migration Service by using a backup and restore flow.\nYou first upload the full database backup and transaction\nlog files to a Cloud Storage bucket. Database Migration Service then actively\nmonitors your bucket, and continuously replicates your data to the destination\nCloud SQL for SQL Server instance.\n\nThis page provides an overview of the key Database Migration Service\nfeatures for homogeneous SQL Server migrations:\n\n- [Supported source and destination](#supported-src-and-dest) lists all SQL Server\n versions supported by Database Migration Service.\n\n- [Continuous migrations data flow](#data-flow-migration-types) provides an end-to-end overview\n of how your data moves in Google Cloud during the migration process.\n\n- [Monitoring](#monitoring)\n gives an introduction for logs and metrics that can\n help you observe the progress and health of your migration job.\n\n- [Encryption](#securing-migration-jobs) looks at how you can migrate\n with encrypted SQL Server backup files.\n\nSupported source and destination databases\n------------------------------------------\n\nYou can use Database Migration Service to migrate between the same SQL Server\nversion and edition, or from earlier versions of\nSQL Server to later versions supported in Cloud SQL, as long\nas you follow the version compatibility guidelines. For more information,\nsee the supported version and edition upgrades for your SQL Server\nversion in Microsoft documentation. For example, see\n[Supported version and edition upgrades (SQL Server 2022)](https://learn.microsoft.com/en-us/sql/database-engine/install-windows/supported-version-and-edition-upgrades-2022?view=sql-server-ver16#upgrades-from-earlier-versions-to-sql-server-2022).\n\nThe following table lists all supported SQL Server source and destination\ndatabases:\n\nContinuous migrations data flow\n-------------------------------\n\nFor homogeneous SQL Server migrations to Cloud SQL,\nDatabase Migration Service supports the\n[continuous migration](/database-migration/docs/overview#migrationconcepts) flow. In this approach, your data is first\nloaded from a full database backup file, then from a differential backup file,\nand then continuously updated based on transaction log files you upload to\na dedicated Cloud Storage bucket.\n[](#lightbox-trigger) **Figure 1.** Data movement during Database Migration Service for SQL Server migrations. (click to enlarge)\n\nAt a high level, your data moves through the migration phases as follows:\n\n1. You upload your backup files to Cloud Storage.\n\n Continuous SQL Server migrations require that you first take a\n full backup of your source database, and then upload the backup file to\n a Cloud Storage bucket.\n For subsequent updates, you can optionally provide a differential backup file,\n and then upload transaction log files.\n You can also automate continuous transaction log creation and uploads.\n - For more information on automating continuous transaction log creation and\n uploads, see\n [Schedule transaction log backups](/database-migration/docs/sqlserver/automate-backup-exports).\n\n - For details on how Database Migration Service uses different types of backup files\n in homogeneous SQL Server migrations, see\n [Supported backup file types](/database-migration/docs/sqlserver/supported-backup-files).\n\n2. When the migration job starts, Database Migration Service loads the latest full\n database backup to the destination Cloud SQL for SQL Server instance.\n\n3. Once the initial load is complete, Database Migration Service switches to the incremental\n load phase. At this point, Database Migration Service performs the following:\n\n 1. If your migration job is configured to use a differential backup file,\n Database Migration Service scans the `diff` folder and loads differential backup\n files to your destination instance. If your migration job is configured\n to use a differential backup file, but Database Migration Service can't find it\n in the Cloud Storage bucket, the migration job shows an error\n while continuously searching the `diff` folder for the differential\n backup file.\n\n Database Migration Service loads differential backup files only once, at the beginning\n of the incremental load phase. When the migration job proceeds to work with\n transaction log files no new differential backup files are recognized when\n you upload them to the `diff` folder.\n 2. Now Database Migration Service continuously scans your Cloud Storage bucket\n for transaction log backup files to replicate on your destination instance.\n\n4. As new data shows up in your source database, you can keep exporting\n the transaction log backup files and uploading them to the same Cloud Storage\n bucket. Database Migration Service picks up all new transaction log backup files and\n replicates them on the destination database.\n\nYou can stop the ongoing replication and promote the migration job when you want\nto switch your application to so that it uses the Cloud SQL for SQL Server\ndestination instance as the production database. For a detailed step-by-step\nmigration guide, see\n[Cloud SQL for SQL Server migration guide](/database-migration/docs/sqlserver/guide).\n\nMonitoring\n----------\n\n[](#lightbox-trigger) **Figure 2.** Sample observability diagram in Database Migration Service. (click to enlarge)\n\nDatabase Migration Service provides extensive logging and observability capabilities\nto help you monitor the migration progress. These features include real-time\ndiagnostics for replication delay and transaction log backup file processing,\nas well as detailed logs for Cloud SQL for SQL Server destination instance health\nand migration job state.\n\nFor more details, see\n[Migration job metrics](/database-migration/docs/sqlserver/migration-job-metrics).\n\nEncryption\n----------\n\nDatabase Migration Service is fully compatible with\n[encrypted SQL Server backups](https://learn.microsoft.com/en-us/sql/relational-databases/backup-restore/backup-encryption). If you upload your\nencryption key to Google Cloud, Database Migration Service can safely decrypt\nyour data and load it to the Cloud SQL for SQL Server destination instance without\ncompromising your data security.\n\nFor more details, see\n[Encrypted SQL Server backup files](/database-migration/docs/sqlserver/backup-file-encryption).\n\nWhat's next\n-----------\n\n- To learn more about SQL Server data and feature support in\n Database Migration Service, see\n [Known limitations](/database-migration/docs/sqlserver/known-limitations).\n\n- To get a complete, step-by-step migration walkthrough, see\n [Cloud SQL for SQL Server migration guide](/database-migration/docs/sqlserver/guide)."]]
