Cloud Sync supports multiple synchronization connections, enabling secure and real-time data synchronization between your Synology storage system and various public cloud storage services.

• Cloud Sync links each connection to one authenticated account on a public cloud service (except for Google Shared Drive, which can create multiple connections for different spaces).
• Each connection can contain multiple tasks, and each task syncs one folder on the cloud with one folder on the Synology NAS in the configured sync direction.
• Cloud Sync supports bi-directional synchronization, one-way synchronization that downloads remote changes only, and one-way synchronization that uploads local changes only.

• Synology C2 Object Storage
• Alibaba Cloud Object Storage Service (OSS)
• Backblaze B2
• Baidu Cloud
• Box
• Dropbox, including Dropbox Business
• Dropbox Team Space
• Google Cloud Storage
• Google Drive, including Google Workspace accounts
• Google Shared Drive
• hicloud S3
• HiDrive
• JD Cloud Object Storage Service (OSS)
• MegaFon MegaDisk
• Microsoft Azure Storage (Global and China)
• Microsoft OneDrive (including Microsoft 365, excluding OneDrive Personal Vault)
• Microsoft OneDrive for Business
• Microsoft SharePoint
• OpenStack Swift
• RackSpace Cloud File
• S3 storage (Amazon S3 compatible cloud services)
• Tencent Cloud Object Storage (COS) (only V5 is supported)
• WebDAV compatible cloud services
• Yandex Disk

• Cloud Sync syncs general and mounted encrypted shared folders.

Not Supported

• Cloud Sync does not support syncing remotely mounted folders on Synology NAS and shared folders on external storage devices.

• Sync tasks can be scheduled to run or suspend during selected time brackets.
• Polling periods control the next search time for file changes on the public cloud.
• Bandwidth control can set the maximum upload or download rate for a single file.

Limits

• Paused connections automatically resume after the Synology NAS restarts, and users must manually pause the connection again if needed.

• Tasks can encrypt data sent to the public cloud.
• Users can assign sync priorities.

• Each sync task can blacklist file types, maximum file size, file names, and file extensions for syncing files and folders.
• The file type blacklist covers music, video, image, document, Google Docs, and Box Docs categories.

• Advanced consistency checks compare the hash of each file between the public cloud and the Synology NAS to enhance sync-result integrity checks.
• Client-side AES-256 encryption secures uploaded files.
• Compression reduces storage consumption for uploaded files.
• Windows and Linux decryption tools are available for data recovery.

• In download-only tasks, Cloud Sync converts Google Docs to Microsoft Office or jpeg formats to maintain offline backup copies.

• Administrators can centrally monitor and control resource usage.
• Administrators can access a centralized view of connections, filterable by user name or by cloud type.
• Administrators can configure the maximum number of concurrent upload/download files from 1 to 20 files.
• Logs include event, date, and time details for each file or folder in each task, and administrators can configure the maximum number of retained log entries from 5 to 100,000.

• Renaming folders during syncing might remove files within the folder.
• Syncing Synology Drive Team folders with remote folders whose names end with a period or space might remove files within those folders.
• Syncing Synology Drive Team folders with remote folders whose names differ from the local path only by capitalization, such as "test" and "TEST", might remove files within those folders.

• Each public cloud has specific limitations and rules. Refer to this help article for details.
• Cloud service providers impose speed limits.
• Cloud service providers impose upload and download file size limits.

• Cloud Sync does not perform incremental updates.
• Whenever a file is modified, it must be re-downloaded and synced even if only part of the file changed.

• Syncing might affect Synology NAS hibernation. Refer to this FAQ for more information.