Set up snapshots in Snapshot Replication:
1. Select a shared folder or LUN.
2. Click Settings > Schedule and select Enable snapshot schedule.
3. Set the time and interval for snapshots.
4. Select Enable immutable snapshots.
This prevents malicious or accidental deletion during the specified Protection period; the recommended period is 7 to 14 days. Once enabled, the snapshot cannot be removed by any means until the system automatically unselects the option when the period ends.
Notes:
- You cannot delete a shared folder or LUN that has immutable snapshots until the protection period ends.
- In Control Panel > Shared Folder > Edit, only the NFS permission is not recorded in a snapshot.
- Data in the recycle bin is also protected by snapshots.
- Do not use Snapshot Replication to protect the surveillance shared folder.
- For ransomware protection, Synology also recommends an offline, encrypted backup and following Backup 3-2-1 and Backup-At-Rest principles.
Sources: [3], [2]