• Target storage:
  • Shared folders and thin-provisioned LUNs in volumes using Btrfs.
  • Thin-provisioned LUNs with advanced features in volumes using ext4.
• Free space:
  • At least 100 MB of available volume space for taking or replicating a shared-folder snapshot.
  • At least 1 GB of available volume space for taking or replicating a LUN snapshot.
• Immutable snapshots are available on supported Synology models.

Manage snapshots with flexible scheduling, retention policies, and preview capabilities.

• Maximum number of snapshots:
  • 65,536 snapshots per system (shared folders and LUNs combined)
  • 1,024 snapshots per shared folder (limited to 128 if the folder is in a tiering plan)
  • 256 snapshots per LUN
  • The exact limits vary by model. For details, refer to your Synology product's software specifications.
  • While keeping excessive snapshots can impact storage efficiency, deleting them in bulk to reclaim space may also affect performance. It's recommended to manage snapshots by deleting them on a regular basis.
• Customizable snapshot schedules with a minimum interval of 5 minutes.
• Snapshot retention:
  • Smart Retention policy: Uses the Grandfather-Father-Son (GFS) retention policy for balanced long-term retention and storage usage.
  • Numbers of latest snapshots to keep: Retains a specified number of the most recent snapshots.
  • Keep all snapshots for: Retains all snapshots created within a specified period.
  • Tiering plan retention: Combines latest-snapshot count and time-based retention rules for shared folders included in a Synology Tiering plan to optimize storage usage.
• Shared-folder snapshots:
  • Snapshot size calculation for space management.
  • Snapshot browsing:
    • Supports previewing and copying snapshot content in File Station or Windows File Explorer.
    • Supports online snapshot preview and individual file downloads. Online preview is not supported for encrypted shared folders.

Replicate snapshots to remote servers for offsite protection and disaster recovery.

• Supported replication topologies:
  • Active-active
  • Extended replication (up to 3 destinations)
  • One-to-many (up to 3 destinations)
  • Hub-to-spoke
• Maximum number of replication tasks:
  • 128 tasks per system (shared folders and LUNs combined)
  • 128 total tasks for all shared folders
  • 64 total tasks for all LUNs
  • The exact limits vary by model. For details, refer to your Synology product's software specifications.
• Customizable replication schedules:
  • Shared folders: Minimum interval of 5 minutes
  • LUNs: Minimum interval of 15 minutes
• Replication transmission and performance:
  • Encrypts replication traffic during transmission.
  • Allows specifying the IP address, port, and preferred network interface for replication.
  • Supports importing the initial replication data to a destination server with an external storage device, reducing the time required for the initial synchronization.
  • Supports configuring the maximum number of concurrent replication tasks to optimize resource allocation. Available only on models with more than two CPU threads.

Recover data from snapshots or perform disaster recovery for replicated storage spaces.

• Recovery via snapshots:
  • Allows browsing, downloading, or copying files and folders from shared folder snapshots.
  • Restores a shared folder or LUN to a previous snapshot.
  • Clones a snapshot to create a new shared folder or LUN.
  • Restores shared-folder files using Windows Previous Versions.
• Recovery via replication tasks:
  • Switchover: Manually switch the roles of the source and destination servers.
  • Failover: Fail over data to the destination server when the source server is unavailable.
  • Forced Failover: Force the destination server to take over even if the source server is still online.
  • Re-protect: Re-establish replication after failover to synchronize data between the source and destination servers.
  • Test Failover: Create a writable replica on the destination server to verify disaster recovery without affecting production services.
  • Cleanup Test Failover: Remove test failover information and optionally keep or delete the test replica.

• NFS permissions are not recorded in snapshots.
• Recycle Bin data is included in snapshots.
• Hybrid Share folders and USB shared folders (usbshare) do not support snapshot or replication tasks.
• Shared folders included in a tiering plan support snapshot tasks but not replication tasks.
• When a shared folder or LUN has a replication task, the latest replicated snapshot cannot be deleted.
• The homes shared folder does not support Restore to this snapshot, switchover, failover, forced failover, test failover, or re-protect.
• WriteOnce shared folders do not support Restore to this snapshot.
• WriteOnce shared folders in Compliance mode do not support switchover or re-protect.