Amazon FSx cost explained: pricing the managed file systems

Quick answer

Amazon FSx pricing depends on which of the four file systems you pick. You pay for provisioned storage capacity (per GB-month), and depending on type, throughput capacity and provisioned IOPS separately. FSx for Windows and NetApp ONTAP bill capacity plus throughput and can use cheaper HDD storage; FSx for Lustre bills per GB-month with performance tied to capacity and is aimed at high-performance computing; FSx for OpenZFS bills capacity plus throughput. Single-AZ is cheaper than Multi-AZ, and ONTAP adds data-tiering to lower cost for cold data.

Amazon FSx is not one product but four managed file systems, each with its own pricing model and its own sweet spot. Getting the cost right starts with picking the right file system, because the price difference between them for the same workload can be large. Then within a type, deployment choices (Single-AZ versus Multi-AZ, SSD versus HDD, provisioned throughput and IOPS) move the bill significantly.

The four FSx file systems

File system	Best for	Priced on
FSx for Windows	Windows/SMB workloads, shared drives	Capacity, throughput, backups
FSx for Lustre	HPC, ML training, high throughput	Capacity (performance tied to size)
FSx for NetApp ONTAP	Enterprise NAS, multi-protocol	Capacity, throughput, plus tiering
FSx for OpenZFS	Linux/NFS, general shared storage	Capacity, throughput, IOPS

FSx for Windows serves SMB shares and bills provisioned capacity plus throughput capacity, with an option for cheaper HDD storage. FSx for Lustre targets high-performance computing and machine learning, pricing per GB-month with performance scaling with provisioned size. FSx for NetApp ONTAP is a full enterprise NAS with automatic tiering of cold data to cheaper capacity. FSx for OpenZFS provides NFS access with separately provisioned throughput and IOPS.

What drives FSx cost

Three dials dominate: provisioned capacity (you pay for what you allocate, not what you use, so over-provisioning wastes money the way an oversized EBS volume does), throughput and IOPS (provisioned separately on several types, so buying more performance than you need is a common overspend), and deployment resilience (Multi-AZ roughly doubles the storage cost of Single-AZ because it replicates across zones). Backups and, on Lustre, optional persistent versus scratch modes add further variance.

Single-AZ versus Multi-AZ

The resilience choice is one of the biggest levers. Single-AZ keeps one copy in one Availability Zone and is the cheaper option, appropriate for dev, test, and workloads that can tolerate a zone-level recovery. Multi-AZ replicates synchronously across zones for high availability and roughly doubles the storage bill, plus it can incur cross-AZ data transfer for clients in other zones. Match the deployment to the actual availability requirement rather than defaulting to Multi-AZ.

Choosing the cheapest FSx fit

Pick the file system that matches your protocol and performance need rather than the most powerful one: HDD on Windows or ONTAP for capacity-heavy, latency-tolerant data; Lustre only when you genuinely need HPC-grade throughput; ONTAP tiering to push cold data to cheaper storage automatically. Right-size provisioned capacity and throughput to real usage, use Single-AZ where availability allows, and treat FSx like any other metered resource you can over-provision. Price the configuration before you deploy against the resource catalog.

FAQ

How is Amazon FSx priced?

You pay for provisioned storage capacity per GB-month, and depending on the file system, provisioned throughput capacity and IOPS separately, plus backups. The four FSx types (Windows, Lustre, NetApp ONTAP, OpenZFS) each have their own model, so the same workload can cost very differently depending on which type and deployment you choose.

Which FSx file system is cheapest?

It depends on the workload. For capacity-heavy, latency-tolerant data, HDD storage on FSx for Windows or NetApp ONTAP tends to be cheapest, and ONTAP can tier cold data to cheaper capacity automatically. Lustre is cost-effective per GB for high-throughput HPC but is not the cheapest for general file sharing. Match the type to your protocol and performance need.

How much does Multi-AZ FSx cost versus Single-AZ?

Multi-AZ roughly doubles the storage cost of Single-AZ because it synchronously replicates data across two Availability Zones for high availability, and it can add cross-AZ data transfer charges for clients in other zones. Single-AZ keeps one copy in one zone and is the cheaper choice for dev, test, and workloads that tolerate zone-level recovery.

Do I pay for FSx capacity I do not use?

Yes, on most FSx types you provision capacity and throughput and pay for what you allocate, not what you actually consume, similar to an oversized EBS volume. Over-provisioning is therefore a common source of waste. Right-size the provisioned capacity, throughput, and IOPS to real usage, and use features like ONTAP tiering to keep cold data on cheaper storage.

What is the difference between FSx for Lustre scratch and persistent?

Scratch file systems are cheaper and intended for temporary, high-throughput workloads where data can be regenerated, offering no long-term durability guarantees. Persistent file systems replicate data within a zone for durability and are priced higher. Choosing scratch for ephemeral HPC or ML data you can recompute is a meaningful cost saving over persistent.

Does C3X price Amazon FSx?

C3X reads your Terraform and prices the storage resources you define, including FSx file systems, against a live catalog before you deploy. That lets you compare deployment choices (file system type, Single-AZ versus Multi-AZ, provisioned capacity and throughput) by their monthly cost in the pull request rather than discovering the difference on the bill.

What to do next

Compare FSx deployment options by cost before you deploy. C3X reads your Terraform and prices your resources against a live catalog. Start with the quickstart.