1. Google Cloud Documentation, "Filestore overview". The first paragraph explicitly states, "Filestore is a fully managed, high-performance file storage service from Google Cloud for applications that require a file system interface and a shared file system for data. Filestore provides a familiar file system experience and is ideal for enterprise applications that depend on NFS."
Source: https://cloud.google.com/filestore/docs/overview
2. Google Cloud Architecture Center, "File storage on Compute Engine". This document compares storage options and recommends Filestore for specific scenarios. In the "Choosing a file storage solution" section, it states, "For workloads that require a Network File System (NFS) protocol and shared file access, Filestore is an effective storage option."
Source: https://cloud.google.com/architecture/file-storage-on-compute-engine
3. Google Cloud Documentation, "Cloud Storage products". This page provides a comparison table of Google's storage services. It categorizes Filestore as "File storage" with the primary access method being "NFSv3" and the use case as "Managed network file share." This clearly distinguishes it from Persistent Disk (Block storage), Cloud Storage (Object storage), and Cloud Bigtable (NoSQL database).
Source: https://cloud.google.com/storage/docs/products