Which ONTAP feature prevents the modification or deletion of backup snapshots?

NetApp SnapLock in Compliance mode is the feature designed to provide immutable, WORM (Write Once, Read Many) data protection. When a volume is configured for SnapLock Compliance, the data and any associated Snapshot copies are locked for a specified retention period. During this period, the data cannot be modified or deleted by anyone, including a system administrator. This provides the highest level of protection against ransomware, which often attempts to delete or encrypt backups to prevent recovery.

A. SnapVault: This is a backup relationship technology; while it can send snapshots to a SnapLock destination, SnapVault itself does not provide immutability.

B. Snapshot autodelete: This feature automatically deletes older snapshots to free up space, which is the opposite of preventing deletion.

D. NDMP: This is a protocol used for backing up NAS data to third-party backup applications; it is not an ONTAP immutability feature.

1. NetApp, Inc. (2022). TR-4526: SnapLock. Section: "SnapLock Compliance," p. 8. States that in Compliance mode, "a file cannot be deleted until it has passed its retention date, even by an administrator."

2. NetApp, Inc. (2022). TR-4574: NetApp Solution for Ransomware. Section: "Immutable Snapshot copies," p. 9. Recommends SnapLock to "prevent Snapshot copies from being deleted by a rogue administrator or ransomware."

3. NetApp, Inc. (2023). ONTAP 9 Documentation: How SnapLock works. This document describes how SnapLock Compliance meets strict regulatory requirements (like SEC Rule 17a-4) for non-erasable, non-rewritable data storage.