Choosing the Right FSx Variant

Start with the protocol or ecosystem requirement, not the workload type: if the application genuinely needs SMB and Windows-native ACLs, FSx for Windows File Server is the only fit among the four. If there's existing NetApp ONTAP tooling, scripts, or SnapMirror-based replication in use, FSx for NetApp ONTAP preserves that investment during migration. If the workload is Linux-based and already built around ZFS snapshot/clone semantics (or simply wants ZFS's storage efficiency features on AWS), FSx for OpenZFS fits without requiring an ONTAP-specific skillset. If the driving requirement is raw parallel-read throughput for HPC simulation or distributed ML training reading a large dataset repeatedly across many nodes, FSx for Lustre is purpose-built for exactly that pattern and is the variant most likely to appear in an ML/HPC-focused exam scenario. When none of these specific requirements apply, EFS (general-purpose NFS) or S3 (object storage) are usually the lower-cost, simpler default.