FlexCache is the NetApp ONTAP feature designed specifically for this use case. It creates a sparse, writable cache of an origin volume in a remote location, such as on a Cloud Volumes ONTAP instance. When the cloud application requests data, it is fetched from the on-premises origin volume and cached locally in the cloud. Subsequent reads are served directly from this low-latency cache. Writes are also performed locally on the cache and then asynchronously sent back to the origin volume. This architecture effectively masks the high latency of the WAN connection for the cloud application while keeping the primary data source on-premises.

B. SnapMirror: SnapMirror is a disaster recovery technology that creates a read-only, asynchronous replica of a volume. It does not provide the required active, writable access for an application.

C. FabricPool: FabricPool is a storage tiering technology that moves inactive (cold) data blocks to a low-cost object store. It does not cache an entire active volume for low-latency remote access.

D. SnapVault: SnapVault is a disk-to-disk backup and archival feature. It creates long-term, read-only Snapshot copies for data retention and restoration, not for providing live application access.

1. NetApp Technical Report 4743: FlexCache in ONTAP 9.

Section: Introduction, Page 4.

Quote: "FlexCache volumes provide a method for transparently caching data from a source (origin) volume on a remote cluster... This caching improves performance by reducing the latency of accessing data over a WAN." This document explicitly details the use of FlexCache for reducing latency in remote and hybrid cloud scenarios.

2. NetApp ONTAP Documentation Center: Concepts Guide - What FlexCache is.

Section: "What FlexCache is"

Quote: "A FlexCache volume is a sparsely populated writeable volume that caches the data of an origin volume... When a client requests data that is not in the cache, the data is fetched from the origin volume and is stored in the FlexCache volume before being served to the client." This confirms its role as a writable cache for remote data access.

3. NetApp ONTAP Documentation Center: Data Protection Guide - Overview of SnapMirror data protection.

Section: "What SnapMirror is"

Quote: "SnapMirror is disaster recovery technology... It provides asynchronous, mirrored data protection. The SnapMirror destination volume is read-only..." This confirms SnapMirror's primary purpose is DR and that the destination is read-only, making it unsuitable for this question's requirements.