• Hybrid Share integrates C2 Storage with on-premises Synology NAS hosts for multi-site file access and collaboration.
• The same Hybrid Share folder can be mounted on multiple Synology NAS hosts for file access across locations.
• A single Hybrid Share folder can be mounted concurrently on up to 10 Synology NAS hosts.
• A Synology NAS host can concurrently mount 5 to 30 Hybrid Share folders, depending on the hardware specifications of the NAS host.
• Hybrid Share provides end-to-end AES-256 encryption.
• Hybrid Share uploads changed data only when transferring data to C2 Storage.
• File access is available through SMB/CIFS, AFP, NFS, FTP, WebDAV, File Station, and Synology Drive.

Requirements

• Hybrid Share requires a Synology NAS model that supports the Btrfs file system, has 2 GB of memory, and runs DSM 7.0.1 or above.
• Hybrid Share requires a Synology Account with a C2 OneStorage Plan subscription.
• New C2 OneStorage Plan subscribers can use a 30-day free trial without credit card information.
• C2 OneStorage Plan supports third-party login using Apple and Google.
• Only administrators or users delegated with sufficient permissions can mount a Hybrid Share folder or convert a shared folder to a Hybrid Share folder in DSM Control Panel > Shared Folder.

File and path limits

• Maximum single file size is 768 GB.
• Maximum path name length is 4 KB (4,000 bytes).

Privileges and permissions

• Hybrid Share synchronizes file privileges exclusively for domain users.
• Hybrid Share synchronizes permission inheritance and removal of inherited permissions for local and domain users on subfolders across all NAS hosts where the Hybrid Share folder is mounted.
• When permissions are modified with Windows File Explorer, Deny rules applied to the Domain Admins group are ignored.

Limitations

• C2 Storage / Hybrid Share is not supported in China.
• Hybrid Share folders cannot be mounted on a high-availability cluster created with two different Synology NAS models.
• Hybrid Share folders cannot be set as sync folders in Synology Drive ShareSync.
• File Station cannot mount remote CIFS/NFS folders or virtual drives to a Hybrid Share folder.
• Hybrid Share folders cannot be moved to another volume after they are mounted on a Synology NAS.
• For more limitations regarding package integration, refer to this article.

• Smart cache centrally stores data on C2 Storage and caches frequently accessed data, or hot data, on local NAS for lower-latency access.
• Users can pin files and folders to the local cache of Hybrid Share folders.
• Frequently accessed cloud data is stored in the local cache to reduce access latency.
• The reserved local cache size must be at least 300 GB.
• The reserved local cache size cannot exceed 90% of the Btrfs volume size.
• The reserved local cache size cannot exceed the quota of the Hybrid Share folder on C2 Storage.
• The minimum storage requirement for the local NAS during Express Box migration is the total size of the data to be migrated plus the planned local cache capacity, which must be at least 300 GB.

Cache eviction and release

• When local cache usage reaches the reserved local cache size, Hybrid Share automatically evicts data with the oldest access time, excluding pinned files and folders, to make space for new data.
• Users can manually release local files from the local cache in File Station.
• If specific file types are excluded from being uploaded to C2 Storage, releasing the local cache of excluded data is not supported to prevent accidental data deletion during automatic or manual space release.

Cache throttling

• Cache throttling slows down writes to the mounted Hybrid Share folder when the Btrfs volume capacity is running low.
• Cache throttling does not affect read speed.
• Write speed is throttled when volume usage reaches 80% on a volume smaller than 1 TB.
• Write speed is throttled when volume space is less than 200 GB on a volume larger than 1 TB.
• Minimum write speed of 128 KB/s is applied when volume usage reaches 95% on a volume smaller than 1 TB.
• Minimum write speed of 128 KB/s is applied when volume space is less than 50 GB on a volume larger than 1 TB.

• Hybrid Share can restore folders to a recovery point to protect data from malicious attacks or accidental actions.
• Hybrid Share supports automatic DSM configuration backup and restoration for instant data recovery.
• Recovery point support is available on Hybrid Share 1.3.0 and above.
• Hybrid Share can retain up to 32 recovery points.
• Hybrid Share can automatically take one scheduled recovery points within 24 hours.
• Hybrid Share can manually take an unlimited number of recovery points within 24 hours.

Limitations

• Snapshot-based data protection for Hybrid Share folders is provided only through C2 Storage recovery points; the local Snapshot Replication package cannot be used on Hybrid Share folders on the local Synology NAS.

• Hybrid Share supports global file locking for data consistency when users collaborate across locations.
• Detailed logs monitor and audit file access activities.
• Logs and global file locking are available on Hybrid Share 1.4.0 and above.
• C2 Encryption Key is required to enable file transfer logs.
• Global file locking is not available for Microsoft PowerPoint 2019 and 2021 for macOS.

• Shared folders larger than the quota of the Hybrid Share folder on C2 Storage cannot be converted to Hybrid Share folders.
• Shared folders with data checksum for advanced data integrity enabled cannot be converted to Hybrid Share folders.
• Shared folders containing any file larger than 768 GB cannot be converted to Hybrid Share folders.
• Shared folders that host specified packages cannot be converted to Hybrid Share folders.
• When a shared folder with shared folder quota enabled begins conversion, the shared folder quota function is disabled.
• Packages that block conversion: Active Backup for Business; Active Backup for Google Workspace; Active Backup for Microsoft 365; Antivirus by McAfee; Antivirus Essential; Audio Station; Container Manager; iTunes Server; Log Center; Media Server, including Media Indexing; Shared Folder Sync; Snapshot Replication; Storage Analyzer; Synology Chat Server; Synology MailPlus; Synology Photos; Surveillance Station; Video Station; Virtual Machine Manager.

• The C2 Storage Web Portal can access a Hybrid Share folder directly from C2 Storage.
• Users can download data from a Hybrid Share folder.
• Users can upload data to a Hybrid Share folder.
• Users can share data with others.
• Users can access data shared by others.
• Users can exclude specific file types from being uploaded to C2 Storage.
• Synology Account and C2 Encryption Key are required to access shared data.

• Maximum single-file upload size is 16 GB.
• Maximum single-file or single-folder download size is 128 GB.
• Single-file download in C2 Storage Explorer with Safari (desktop/iOS) or Firefox is limited to 1 GB.
• A single file can be shared with up to 20 users.
• A single Hybrid Share folder can be delegated to up to 10 users.
• A single file can be downloaded or previewed up to 50 times per day.
• A single folder can be downloaded up to 20 times per day.
• File and folder download counts are tracked separately.

Actual maximum preview size may vary by operating system and device.

• With file type exclusions enabled, excluded items are not uploaded to C2 Storage.
• The default exclusions cannot be removed.
• Names matching .DS_Store, Thumbs.db, or desktop.ini are excluded by default.
• Names ending with @SynoResource, .DS_Store, or @SynoEAStream are excluded by default.
• Additional exclusions are automatically added and can be removed at the user's discretion. For details, refer to this article.

• Users can view recovery point contents.
• Users can download individual files from a recovery point.
• Users can restore folders to a previous recovery point.

Restoring a Hybrid Share folder to a recovery point will:

• Unpin all files and folders previously pinned in DSM > File Station.
• Lose all historical versions when the folder is enabled as a Team Folder in Synology Drive Admin Console > Team Folder and versioning is enabled in Synology Drive Admin Console > Team Folder > Versioning.

• When data is accessed with C2 Storage Explorer on a Linux computer, symbolic links are not displayed.
• When a folder is downloaded with C2 Storage Explorer on a Linux computer, symbolic link information is not downloaded.