Cloud Sync
With Cloud Sync, you can seamlessly sync and share files among your Synology NAS and multiple public cloud services, including:
- Synology C2 Object Storage
- Alibaba Cloud Object Storage Service (OSS)
- Azure Storage
- Backblaze B2
- Baidu Cloud
- Box
- Dropbox (including Dropbox for Business)
- Dropbox Team Space (Dropbox Business)
- Due to Dropbox's API limitations for team space, team members cannot sync the local first-layer sub-folder with Dropbox Team Space. Refer to this article for details.
- Google Cloud Storage
- Google Drive (including Google Workspace My Drive)
- Google Shared Drive
- hicloud S3
- HiDrive
- JD Cloud Object Storage Service (OSS)
- MegaFon MegaDisk
- Microsoft OneDrive (excluding OneDrive Personal Vault)
- Microsoft OneDrive for Business
- Microsoft SharePoint Online (document library only)
- OpenStack Swift compatible cloud services (including RackSpace, RackSpace UK)
- S3 storage (Amazon S3 compatible cloud services)
- Tencent Cloud Object Storage (COS)
- WebDAV
- Yandex Disk
Create New Connections
To sync files among your Synology NAS and public cloud services, you need to create connections on Cloud Sync to link to the service provider by using your user credentials.
To create a new connection:
- On the Cloud Sync user interface, click on the Create icon at the upper-left corner to start the wizard.
- Choose one of the following public cloud services to sync files with and click Next.
- Synology C2 Object Storage: Input Access key, Secret key, and Bucket name.
- Baidu Cloud, Box, Dropbox, Dropbox Team Space, Google Drive, HiDrive, MegaFon MegaDisk, and Microsoft OneDrive (including OneDrive for Business and SharePoint): Sign in with your user credentials.
- WebDAV: Input the server address, your account and password. Server address should follow the formats specified below:
- Input http or https URLs of the intended WebDAV server, with custom port number after the colon (optional), e.g. http://mywebdavserver.synology.me:5005 or https://mywebdavserver.synology.me:5006
- Cloud Sync will connect to the server via http if the URL does not imply http or https.
- If port number is not specified in the URL, Cloud Sync will access port 80 in http connections, and port 443 in https connections.
- Path can be appended to the URL, e.g. https://mywebdavserver.synology.me:5006/webdav/folder
Note: Please note that the entered address cannot contain "." or "..".
- Yandex Disk: Input your account and password. An app password is required by Yandex. (Learn more)
- Google Cloud Storage: Sign in with your user credentials, then Project ID and Bucket name.
- Google Shared Drive: Sign in with your user credentials, then choose only one shared drive.
- Microsoft SharePoint Online: Sign in with your user credentials, then choose only one document library under one of the sites.
- RackSpace: Input username and API Key, and choose location and Container in the next page.
- OpenStack Swift compatible cloud services: Input the identity server address and choose the KeyStone protocol version which the server supports:
- Version 1.0: Input username and API Key
- Version 2.0: Input username, password, Tenant ID or Tenant name (optional).
- Version 3.0: Input username, password, Tenant ID or Tenant name (optional), and Domain ID or Domain name (optional).
- You can choose the location and Container on the next page after passing the identity service
- S3 storage: Select a server (Amazon S3, Amazon S3 China, or input a server address directly), then input the Access key, Secret key and Bucket name. If users want to enter user-specified S3 service hosts, they should enter something like "s3.amazonaws.com", or "api.suite-stockage-cloud.sfrbusinessteam.fr" in the S3 Server Address field.
- hicloud S3: Input Access key, Secret key, and Bucket name.
- Azure Storage: Select a server, input the Blob Storage Access key, and select a Blob container.
- Backblaze B2: Input keyID and application key, and select a Bucket.
- Alibaba Cloud OSS: Input Access key and Secret key, and select a Bucket.
- Tencent Cloud COS: Input Secret ID and Secret key, and select a Bucket.
- JD Cloud OSS: Select region, input Access key and Secret key, and select a Bucket.
- Once authentication has been successful, fill in the following fields and then click Next.
- Connection name: This name will show on the connection list.
- Local path: Select a local folder. All directories and files within this folder will be synced to the remote folder.
- Remote path: Select a remote folder. All directories and files within this folder will be synced to the local folder.
- Sync direction: Select whether you want the sync to be Bidirectional,Download remote changes only, or Upload local changes only.
- Check the box next to Data encryption to enable client-side data encryption.
- Check the box next to Don't remove files in the destination folder when they are removed in the source folder. if needed.
- Schedule settings: Go to this section to enable your schedule for file syncing.
- To further adjust your sync settings, click Advanced settings.
- You can prevent certain files from being synced by unchecking any folders you don't want to sync, by setting a max file size limit, or filtering out certain file names or file extensions:
- By folder: Uncheck any sub-folders you don't want to sync.
- By maximum file size: If a file is bigger than your specified size, it will not be synced.
- By file name: Any file with the designated file name will not be synced.
- File extension: Any designated file extension will not be synced. Add *.[extension] to the table, e.g. *.iso.
- You can prevent certain files from being synced by unchecking any folders you don't want to sync, by setting a max file size limit, or filtering out certain file names or file extensions:
- Click Apply to save your settings.
Note:
- Each user credential can only be used for creating one connection. You can create multiple connections all with different user credentials, but not duplicate connections with the same user credential.
- If you selected Upload local changes only or Bidirectional for Sync direction, Cloud Sync will synchronize all subfolders and files within the selected folder.
- Due to Baidu's limitations, you are only allowed to sync files to the My Application's Data > Cloud Sync folder in your Baidu Cloud storage. The storage limitation per folder is 100 GB.
- File or folder names that end with a period (.) or a space will be renamed as "file name._DiskStation_modified date_TailCharacterConflict".
- When using Cubby via WebDAV, if a folder containing files is deleted, Cubby server will recreate it after syncing. For example, if you delete "folder /A", Cubby will download the folder and its contents as "folder /a". Additionally, files with the file name ".hidrive" or file extension ".webupload" will not be synced by WebDAV.
- As a general rule, files will not be synced by Cloud Sync under the following circumstances:
- The folder or file path contains NFD characters or the following characters:
: \ / - The file name starts with any of the following:
._ ~.SYNOPPSDB - The file/folder name is any of the following:
.ds_store, desktop.ini, @eadir, thumbs.db, .SynologyWorkingDirectory, #recycle, Icon\r, $Recycle.Bin, @sharebin, @SynologyCloudSync, cloudsync_encrypt.info, @ActiveBackup, ActiveBackupData, #snapshot, ActiveBackupForOffice365, ActiveBackupForGSuite - The folder or file in the @tmp folder of the root folder.
- The folder or file path is longer than 2,048 characters.
- The file name is longer than 255 characters.
- The folder or file is located in a mount point or an external storage device.
- The folder or file under a folder is being mounted using a bind mount.
- The folder or file path contains NFD characters or the following characters:
- In special cases, files will not be synced by Cloud Sync under the following circumstances:
- For Synology C2 Object Storage if:
- The folder or file path is longer than 1,024 characters.
- The size of a single file exceeds 5 TB.
- The folder or file path contains the following characters:
" < > | { ^ } % ` ] [ ~ # - The folder or file name is . or ..
- For Hybrid Share if:
- The size of a single file exceeds 768 GB.
- For Alibaba Cloud OSS if:
- The folder or file path is longer than 1,023 characters.
- The size of a single file exceeds 48.8 TB.
- The folder or file name is . or ..
- For Amazon S3 if:
- The folder or file path is longer than 1,024 characters.
- The size of a single file exceeds 5 TB.
- The folder or file path contains the following characters:
" < > | { ^ } % ` ] [ ~ # - The folder or file name is . or ..
- For hicloud S3 if:
- The folder or file path is longer than 255 characters.
- The size of a single file exceeds 1 TB.
- The folder or file path contains the following characters:
" < > | { ^ } % ` ] [ ~ # - The folder or file name is . or ..
- For Backblaze B2 if:
- The folder or file name is .bzEmpty.
- The folder or file name is longer than 250 characters.
- The folder or file path is longer than 1,024 characters.
- For Baidu Cloud if:
- The file name starts with a period (.).
- The file/folder name is, or contains any of the following:
.baohe.cache - The folder or file name contains the following characters:
* ? \ " < > | - The storage space has reached the 100 GB limit.
- The size of a single file exceeds the limit of Baidu Cloud membership.
- For Box if:
- The size of a single file exceeds your account limit.
- The type of the file is bookmark.
- For Dropbox and Dropbox Team Space if:
- The file name starts with any of the following:
.dropbox.cache - The file/folder name is, or contains .dropbox or .dropbox.attr.
- The file has been uploading for over 7 days.
- The size of a single file exceeds 350 GB.
- The number of folders exceeds 5,000. (Learn more)
- Team folders are encrypted.
- The file type is Dropbox Paper.
- The file name starts with any of the following:
- For Google Cloud Storage if:
- The size of a single file exceeds 5 TB.
- The folder or file path contains the following characters:
* ? # [ ] \r \n - The file/folder name is blank.
- The folder or file path is longer than 1,024 characters.
- For Google Drive and Google Shared Drive if:
- The size of a single file exceeds 5 TB.
- For JD Cloud OSS if:
- The folder or file path is longer than 1,021 characters.
- The size of a single file exceeds 19 TB.
- The folder or file path contains the following characters:
# % + - The folder or file name is . or ..
- For MegaFon MegaDisk if:
- The folder or file path contains the following characters:
* ? " < > |
- The folder or file path contains the following characters:
- For Azure Storage if:
- The size of a single file exceeds 4.75 TB.
- The folder or file name is .synoemptyblob.
- The full file path is longer than 1,024 characters.
- The file name is longer than 255 characters.
- For Microsoft OneDrive if:
- The type of the file is a note document.
- The size of a single file exceeds 250 GB. (Default: 100 GB)
- The file name begins with a space or Windows.
- The folder is shared by others.
- The folder or file name contains the following characters:
: * ? " < > | \ /
- For Microsoft OneDrive for Business if:
- The type of the file is a note document.
- The size of a single file exceeds 250 GB. (Default: 100 GB)
- The file name begins with a space.
- The file name is longer than 128 characters.
- The full file path is longer than 308 characters.
- The folder or file name contains the following characters:
\ / : * ? "< >| - The folder or file name ends with the following:
. - The folder or file name is one of the following:
forms ~ - The folder or file name contains the following:
_vti_
- For Microsoft SharePoint Online if:
- The size of a single file exceeds 15 GB.
- The file name is longer than 128 characters.
- The full file path is longer than 308 characters.
- The folder or file name contains the following characters:
\ / : * ? "< >| - The folder or file name ends with the following:
. - The folder or file name is one of the following:
forms ~ - The folder or file name contains the following:
_vti_
- For OpenStack Swift compatible cloud services if:
- RackSpace
- RackSpace UK
- The folder or file path is longer than 1,024 characters.
- The folder or file path contains the following characters:
?
- For Tencent Cloud COS if:
- The folder or file path is longer than 797 characters.
- The size of a single file exceeds 48.8 TB.
- The folder or file path contains the following character:
? ~ - The folder or file name is . or ..
- For Synology C2 Object Storage if:
- Cloud Sync on DSM cannot instantly sync the file changes made on containers; likewise, Cloud Sync on containers cannot instantly sync the file changes made on DSM.
- When setting the file names that you don't want to sync, file names will be considered the same if one file name is capitalized and the other has the same name but in lower case (e.g., A.txt and a.txt) on Windows; however, they will be considered different file names on Linux and Mac systems.
- Cloud Sync and the following services follow the OAuth authentication standard: Baidu Cloud, Box, Dropbox, Google Cloud Storage, Google Drive, Google Shared Drive, MegaFon MegaDisk, Microsoft SharePoint Online, and Microsoft OneDrive. OAuth 2 requires another server (which is hosted by Synology and located in Taiwan) to complete the authentication. Your Synology NAS will not remember or keep your account password. Your user credentials will only be used for the file transfer and syncing. Cloud Sync will not access or disclose any other personal account information such as contacts.
- Cloud Sync does not impose any single file size limit. You can sync as big a file as the public cloud services allow.
- Support for MegaFon Megadisk allows you to use Synology NAS as backup storage for Megadisk. Please note that, depending on your location and various conditions, the upload speed from Synology NAS to Megadisk might be limited, so we do not encourage using Megadisk as backup storage for your Synology NAS.
- Google Cloud Storage Nearline Storage Class is designed for data that is not frequently modified, so when you edit or delete a file, early deletion charges may apply.
- When uploading to Google Cloud Storage, Cloud Sync will not enable object versioning.
- If a single file exceeds the allocated segment size, OpenStack Swift will upload it using Dynamic Large Objects.
- OpenStack Swift Container name cannot exceed 255 characters and cannot include '/'.
- Data encryption:
- To enable data encryption, you must have read-write permission to the remote root folder.
- Once you have enabled encryption, you cannot disable it or change its password.
- Local files on your NAS will remain unencrypted.
- Each public cloud account has only one encryption key.
- Once encryption has been enabled, Cloud Sync will create a folder named @SynologyCloudSync on the public cloud. Please do not change the files within that folder.
- An Export button will appear in Settings upon first use. Click the button to export the key, and keep it in a safe place.
- Amazon Infrequent Access Storage is designed for data that is not frequently modified, so when you edit or delete a file, early deletion charges may apply.
- When configuring a Google Drive sync task to be Download remote changes only, you can also enable Convert Google online documents to Microsoft Office or jpeg formats to keep an offline copy of your Google Docs. Note that the changes made to the offline office documents will not be converted and updated back to Google Docs.
- With Enable advanced consistency check ticked, Cloud Sync compares the hash (in addition to file size and last modified time) of each file between the public cloud and the NAS to enhance the integrity check of the sync results. This will require more time and system resources, and depends on the public clouds' support for advanced attributes. Please refer to the bottom of the page for more information.
- Bucket name must comply with the following rules:
- For Amazon S3:
- The name length must be between 3 and 63 characters.
- The name must start with a lowercase letter or number.
- The name can only contain lowercase letters, numbers, or the following:
. - - The name must not be formatted as an IP address (e.g., 192.168.5.4).
- The name cannot begin with xn--.
- For Backblaze B2:
- The name length must be between 6 and 50 characters.
- The name cannot start with b2-.
- For hicloud S3 and other cloud services compatible with Amazon S3:
- The name length must be between 3 and 63 characters.
- The name must start with a lowercase letter or number.
- The name can only contain lowercase letters, numbers, or the following:
. -
- For Alibaba Cloud OSS:
- The name length must be between 3 and 63 characters.
- The name must start with a lowercase letter or number.
- The name can only contain lowercase letters, numbers, or the character -.
- For Tencent Cloud COS:
- The name length cannot exceed 50 characters.
- The name cannot begin or end with -.
- The name can only contain lowercase letters, numbers, or the character -.
- For JD Cloud OSS:
- The name length must be between 3 and 63 characters.
- The name must start and end with a lowercase letter or number.
- The name can only contain lowercase letters, numbers, or the character -.
- Cloud Sync supports Amazon Infrequent Access (IA), Reduced Redundancy Storage (RRS), and S3 Standard for file uploads and downloads, but does not support Glacier for file uploads and downloads.
- Cloud providers such as Aliyun, Tencent, or JD Cloud do not support Glacier for file uploads and downloads.
- As a general rule, folders in remote destinations will not be listed by Cloud Sync under the following circumstances:
- The folder contains the following characters:
/ \ - The folder does not have a folder name.
- The folder name ends with a space.
- The folder contains the following characters:
- Cloud Sync only supports Tencent Cloud COS V5.
- Drive SDK API must be enabled on Google Admin console to allow data synchronization between Synology NAS and Google Workspace My Drive.
- Cloud Sync supports only block blob data type in Azure storage.
- Google Shared Drive can contain a maximum of 500,000 files and folders, and nest up to 100 subfolders. For more information, please refer to this page.
- Cloud Sync does not support syncing files in Google Drive Shared with me, Computers, and Shortcuts.
- To sync the team folders of upgraded Dropbox Business accounts (Team Space), select Dropbox Team Space when creating the connection. To sync other folders or member folders in Dropbox, select Dropbox.
- If you enable Object Lock on Backblaze B2, Cloud Sync will not be able to delete the folder on Backblaze B2 when you delete its corresponding folder on your Synology NAS. This may affect syncing performance, as Cloud Sync constantly tries to delete the remote folder until the retention period for the data is over.
Manage Connections
Once a connection has been successfully created, you can view and modify the connection information.
To manage connections:
- Select the connection you want to edit from the connection list on the left panel.
- Under the Overview tab, click Manage to do any of the following:
- Pause syncing: Pause the syncing operation.
- Resume syncing: Resume the syncing operation.
- Unlink: Remove the connection of your Synology NAS and the public cloud service.
- Edit connection: If authorization of your public cloud account has been revoked or expired, you can click Edit connection to update your information and connect again.
To manage schedule settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Schedule > Schedule settings to configure the following:
- Check the box Enable Schedule Settings to enable the schedule for file syncing.
- Use the scheduling grid to set the schedule for file syncing:
- Run: File syncing will be performed during the selected period.
- Suspend: No file will be synced during the selected period.
- Click Apply to save your settings.
Note:
- Sync tasks will be terminated when entering the suspend mode.
To edit the settings of a connection:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings > General settings to configure the following:
- Connection name: This name will appear on the connection list.
- Polling period: After Cloud Sync has finished syncing with the public cloud, Cloud Sync will sync again after the set period of time.
- Click Apply to save your settings.
Note:
- Polling period refers to how often Cloud Sync polls for changes on the public cloud and syncs the changes to the local folder. For example, if you set your polling period as 1 hour, Cloud Sync will connect to the public cloud and search for file changes every hour. The maximum polling period is one day (86,400 seconds).
To manage Traffic Control:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings > Traffic Control to configure the following:
- Maximum upload rate
- Maximum download rate
- If the value of this field is 0, it means that there is no limit to the rate of file transfer.
- Click Apply to save your settings.
Note:
- The traffic control setting applies to the entire public cloud connection, and is shared by all files being transferred concurrently.
To manage Synology C2 Object Storage advanced settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings and under Advanced settings, do the following:
- Select the size of the upload part.
- Click Apply to save your settings.
To manage S3 Storage advanced settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings and under Advanced settings, do any of the following:
- Select a storage class.
- Enable server side encryption (AES-256).
- Select the size of the upload part.
- Click Apply to save your settings.
To manage Alibaba Cloud OSS advanced settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings and under Advanced settings, do any of the following:
- Enable server side encryption (AES-256).
- Select the size of the upload part.
- Click Apply to save your settings.
To manage OpenStack Swift advanced settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings and under Advanced settings, do the following:
- Select the segment size.
- Click Apply to save your settings.
To manage Backblaze B2 advanced settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings and under Advanced settings, do the following:
- Select the size of the upload part.
- Click Apply to save your settings.
To manage hicloud S3 advanced settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings and under Advanced settings, do the following:
- Enable server side encryption (AES-256).
- Select the size of the upload part.
- Click Apply to save your settings.
To manage Tencent Cloud COS advanced settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings and under Advanced settings, do the following:
- Select the size of the upload part.
- Click Apply to save your settings.
To manage JD Cloud OSS advanced settings:
- Select the connection you want to edit from the connection list on the left panel.
- Go to Settings and under Advanced settings, do the following:
- Select the size of the upload part.
- Click Apply to save your settings.
Manage Sync Task List
After successfully connecting with the public cloud services, you can view, add, delete, or edit your sync tasks.
To add a sync task:
- Select a connection from the connection list on the left.
- Go to the Task List tab.
- Click Create and follow the wizard to create a new sync task.
Note:
- When selecting a folder to sync, it cannot be in the same directory as one already synced in the same connection.
To remove a sync task:
- Select a connection from the connection list on the left.
- Go to the Task List tab.
- Select a sync task and click Delete.
Note:
- After deleting a task, a full re-sync might be required if you wish to link again. When you set up a new connection, Cloud Sync will automatically compare existing files and only upload/ download the changes that have been made.
To manage Cloud Sync selective sync settings:
Selective Sync is a feature of the Cloud Sync application that allows you to filter the files or select the folders you want to sync to the public cloud service. Selective Sync allows you to ensure you have only the files you need on the public cloud service or vice versa.
- Select a public cloud service from the connection list on the left.
- Go to the Task List tab.
- Select a sync task and click Edit.
- In the Folder tab, select the folders you want to sync and click OK to save your settings.
- In the File Filter tab, you can configure the following options:
- You can prevent certain files from being synced by setting a maximum file size.
- Maximum file size should be between 1~10,240 MB, with 0 meaning unlimited.
- You can prevent certain files from being synced by entering the file names or the file extensions. Check the files or file extensions that you do not want to be synced.
- File name: The maximum length of the file name is 255 characters.
- File extension: Add *.extension to the table, e.g. *.iso. The maximum length of the file extension is 255 characters.
- You can prevent certain files from being synced by setting a maximum file size.
- Click OK to save your settings.
To modify sync direction:
- Select a public cloud service from the connection list on the left.
- Go to the Task List tab.
- Select a sync task and click Task settings.
- In the Settings tab, configure any of the following:
- Sync direction: Select whether you want the sync to be Bidirectional,Download remote changes only, or Upload local changes only.
- Check the box next to Don't remove files in the destination folder when they are removed in the source folder.if needed.
Note:
- Cloud Sync will sync all newly added files and folders by default.
Manage Cloud Sync from DSM System Tray
After you have installed and launched Cloud Sync, a package icon will appear at the top-right corner of your DSM system tray. You can easily and efficiently manage Cloud Sync and perform the following actions from the system tray:
- Monitor recently modified files.
- View the transfer speed and progress for current transfers.
- Pause or resume your connections.
- Open the paired sync folders.
- Launch Cloud Sync.
Settings
Administrators can click the Settings icon on the upper-left corner and under Administrator Controls, specify Cloud Sync database location, maximum concurrent uploads/downloads, maximum number of logs kept, and switch to administrator mode.
To specify the database location:
- Select a volume in the Database Location Settings dropdown menu.
- Click OK to save your settings.
To specify the concurrent uploads/downloads:
- Select a number in the Concurrent uploads/downloads dropdown menu.
- Click OK to save your settings.
To specify maximum records in history log:
- In the Maximum records field, input a number between 5 and 100,000.
- Click OK to save your settings.
To enable administrator mode
- Select Enabled in the Admin mode drop-down menu to manage the connections of all Cloud Sync users. You can specify the order of these connections by user account or cloud type in the overview.
- Click OK to save your settings.
For Advanced Users
To ensure your files and folders sync correctly, please note the following information.
Supported file attributes of the public clouds
Platform | File hash | Last modified time |
---|---|---|
Synology C2 Object Storage | O (md5) | X |
Alibaba Cloud OSS | O (md5) | X |
S3 Storage | O (md5) | X |
Backblaze B2 | O (sha1) | O (1) |
Baidu | O (md5) | X |
Box | O (sha1) | O |
Dropbox | X | O |
Dropbox Team Space | X | O |
Google Cloud Storage | O (md5) | O (1) |
Google Drive | O (md5) | O |
Google Shared Drive | O (md5) | O |
hicloud S3 | O (md5) | X |
HiDrive | X | X |
JD Cloud OSS | O (md5) | X |
MegaFon MegaDisk | O (md5) | O |
Azure Storage | O (md5) | O (1) |
Microsoft OneDrive | O (sha1) | O |
Microsoft OneDrive for Business | X | X |
Microsoft SharePoint Online | O (QuickXOR) | X |
OpenStack Swift | O (md5) | O (1) |
Tencent Cloud COS | O (md5) | X |
WebDAV | X | X |
Yandex | X | X |
1: These public cloud providers do not allow the last modified time attribute to be updated, but provides a custom file attribute field for third-party apps like Cloud Sync. Cloud Sync will save the last modified time in the customized file attribute field. This means Cloud Sync's last modified time will not be updated on the public cloud web interface and other sync clients.
Note:
- Due to the file system limitation, after you modified the data on your Synology NAS, Last modified time of the directory on your cloud service and Synology NAS may be different.
- Only Box, Dropbox, Google Drive, MegaFon MegaDisk, and OneDrive allow third parties to update the last modified time, meaning that the last modified time of other public cloud services is always the time when files are uploaded.
- Hash values are not available for files uploaded to S3 Storage, Alibaba Cloud OSS, Tencent Cloud COS, or JD Cloud OSS via multi-part upload.
- Hash values are not available for files uploaded to OpenStack Swift via Dynamic Large Object upload.
- Hash values are not available for files uploaded to Backblaze B2 via b2_upload_part upload.
- Cloud Sync uses Google Cloud Storage's md5 hash. The crc32 hash of composite object is not adopted.
- Increasing the number of concurrent uploads/downloads can improve synchronization performance when the network and resource conditions allow.
Metadata that will not be synced to your public cloud services:
- UNIX read/write and execution permissions.
- Windows ACL.
- Mac's extended attributes.
- Last modified time of the folders.
- Last modified time of the files (for Baidu Cloud, Microsoft OneDrive for Business, Amazon S3, WebDAV, Yandex, Alibaba Cloud OSS, Tencent Cloud COS, and JD Cloud OSS).
Default action for conflicted copy:
If modifying the same file at the same time
If a file or directory is modified on both your local Synology NAS and remote public cloud account at the same time, Cloud Sync will try to keep the local changes as much as possible, and the remote changes will be saved as one revision if the cloud service supports versioning.
If syncing files with the same names
When Cloud Sync encounters two files with the same name on public cloud storage (e.g., Google Drive), it syncs both files and adds "(1)" to the end of one filename.
Cloud Sync may affect Synology NAS hibernation:
Refer to this article to learn more about how to prevent Cloud Sync from affecting Synology NAS hibernation.
Why does Cloud Sync continuously download the same file from Baidu Cloud/Azure Storage?
After files have been uploaded to Baidu Cloud/Azure Storage, Cloud Sync will compare the file hash on both sides to confirm consistency. We found that in many cases, Baidu/Azure Storage will respond with an incorrect hash value, causing Cloud Sync to detect that the files on the public cloud differ from those on your Synology NAS. Because of this, Cloud Sync will try to align the versions, and commence sync again, causing the repeated download of the same file.
Backup and Restore
You can back up Cloud Sync and restore it to a previous version via Hyper Backup.
To back up Cloud Sync:
- Go to Hyper Backup > Create > Data backup task to create a backup task.
- Follow the Backup Wizard instructions, and choose Cloud Sync when you are prompted to select applications to back up.
- After the backup task is complete, all current tasks and settings will be backed up.
To restore Cloud Sync:
- Go to Hyper Backup > Restore > Data to restore the desired backup task.
- After the restore task is complete, the backed up tasks and settings will be restored. Existing tasks and settings will be overwritten.
Why is Cloud Sync slower than other cloud services' PC applications?
Due to the below limitations, Cloud Sync might take longer to sync files with public cloud services than the official PC applications such as Dropbox and Baidu.
- Speed limits imposed by cloud service providers: Although no public cloud service provider has disclosed any information related to this topic, it is highly possible that public cloud servers communicate with their official PC applications through a dedicated tunnel/protocol, or impose bandwidth limitations on third-party applications that access their services on a regular basis (such as Cloud Sync).
- No incremental update: Every time a file is modified, Cloud Sync must re-download and sync the entire file even if only partial modification was made. However, the official applications for PCs offered by cloud service providers support directly downloading and syncing only the modified content, thereby reducing the time required for synchronization.
- No local network sync: Certain public cloud service providers offer LAN sync, a technique that allows one client to obtain files from existing clients in the same local area network (LAN), thus significantly boosting sync speed. However, LAN sync accesses files in client computers without notifying them, which could possibly become a security backdoor. Therefore, this feature is not included in Cloud Sync.
Given the above limitations, the syncing performance of Cloud Sync shall continue to be enhanced, while also maintaining the safety and security of your Synology NAS.