Cloud Sync

DSM Version

Cloud Sync


  • Safe and secure real-time data synchronization between Synology NAS and multiple public cloud storage services
  • Flexible and customizable options such as sync directions, schedule arrangements, and bandwidth control
  • Centralized management for administrators to monitor and control resource usage


  • Supported cloud storage services include:
    • Synology C2 Object Storage
    • Alibaba Cloud Object Storage Service (OSS)
    • Amazon S3 compatible cloud services
      • Amazon S3
      • hicloud S3
    • Backblaze B2
    • Baidu Cloud
    • Box
    • Dropbox (including Dropbox for Business)
    • Dropbox Team Space (Dropbox Business) (See limitation 1)
    • Google Cloud Storage
    • Google Drive (including Google Drive for Work)
    • HiDrive
    • JD Cloud
    • Megafon Megadisk
    • Microsoft Azure (Global and China)
    • Microsoft OneDrive (including Microsoft 365 and OneDrive for Business)
    • OpenStack Swift compatible cloud services
      • RackSpace
      • RackSpace UK
    • Tencent Cloud Object Storage (COS)
    • WebDAV
    • Yandex Disk
  • Maximum number of concurrent upload/download files: Between 3 and 20 files
  • Maximum number of records to retain in history: Between 5 and 100,000 entries
  • Supports flexible synchronization options:
    • Bi-directional synchronization
    • One-way synchronization - download remote changes only
    • One-way synchronization - upload local changes only
  • Supports syncing general and encrypted shared folders
  • Supports advanced consistency check by comparing the hash of each file between the public cloud and the Synology NAS to enhance the integrity check of the sync results
  • Supports multiple synchronization connections
  • Supports scheduling sync tasks by choosing the specific time bracket when the task will be running or be suspended
  • Supports configuring polling period to control the next search time for file changes on the public cloud
  • Supports bandwidth control for maximum upload/download rate for a single file
  • Ensures security and reduces storage consumption of uploaded files with client-side AES-256 encryption and compression
  • Maps and syncs single or multiple folders between the public cloud and the Synology NAS in a single connection
  • Offers the option to choose whether to re-fetch or remove files from your public cloud when they're deleted locally
  • Offers administrator mode for centralized user and cloud type management
  • Converts Google Docs to Microsoft Office or jpeg formats in download-only tasks to maintain an offline backup copy
  • Blacklist of file types (music, video, image, document, Google Docs, Box Docs), maximum file size, file name, and file extension for syncing files and folders for each syncing task
  • Provides logs of detailed information of the event, date, and time for each file or folder for each task
  • Offers Windows and Linux decryption tools for data recovery


  1. Following Dropbox's API updates for team spaces in January 2024, users must update Cloud Sync to version 2.7.0 or above for compatibility. If you are a Dropbox Team Space administrator, unlink and re-establish the connection to ensure proper syncing
  2. Due to Dropbox's new API limitation, team members with full top-level permission cannot sync local changes made on the first-layer sub-folder to Dropbox currently. Refer to this FAQ for more information
  3. Syncing mounted and external shared folder on the Synology NAS is not supported (EDS14 is excluded)
  4. Speed limits are imposed by cloud service providers
  5. Upload and download file size limitations are imposed by cloud service providers
  6. Files with file name limitation imposed by cloud providers cannot be synced (Refer to this link for more information)
  7. No incremental updates. Whenever a file is modified, it must be re-downloaded and synced even if only partial modification was made