aws_fsx_windows_file_system cost estimation
A managed SMB file system with Active Directory integration. Bills per GB of provisioned storage plus throughput; 32 GB SSD Single-AZ is ~$4/month, scaling with capacity.
An aws_fsx_windows_file_system provides fully-managed SMB file shares integrated with Active Directory — the FSx flavor for Windows workloads, lift-and-shift file servers, and shared application data. Cost is provisioned storage per GB-month plus provisioned throughput, with the rate set by storage type (SSD vs HDD) and deployment (Single-AZ vs Multi-AZ).
A small 32 GB SSD Single-AZ file system is only ~$4/month, but real deployments provision hundreds of GB to terabytes, and Multi-AZ roughly doubles the storage rate by replicating to a standby in a second AZ. Throughput capacity is provisioned separately and is a common over-spend — picking a high throughput tier "for headroom" that the workload never uses.
The levers: storage capacity (provision to the working set), storage type (HDD for throughput-oriented, latency-tolerant data; SSD for general), deployment option (Multi-AZ only where you need cross-AZ durability), and throughput (size to actual need).
c3x prices the file system from storage_capacity, storage_type, and deployment_type, so the provisioned cost — including the Multi-AZ premium — is visible before deployment.
Terraform example
A minimal but realistic configuration that C3X can estimate.
resource "aws_fsx_windows_file_system" "shares" {
storage_capacity = 300
storage_type = "SSD"
subnet_ids = [aws_subnet.app.id]
throughput_capacity = 16
deployment_type = "SINGLE_AZ_1"
active_directory_id = aws_directory_service_directory.main.id
}Pricing dimensions
What you actually pay for when you provision aws_fsx_windows_file_system.
| Dimension | Unit | What's being charged |
|---|---|---|
| Provisioned storage | per GB-month | Billed for provisioned capacity at the SSD or HDD rate. Multi-AZ roughly doubles the rate (replicated standby). SSD Single-AZ ~$0.13/GB-month → 32 GB ≈ $4.16/month |
| Throughput capacity | per MB/s-month | Provisioned independently of storage. Over-provisioning throughput is a common cost; size to actual need. |
| Backups | per GB-month | Automatic and manual backups stored separately, billed per GB-month. Usage-based. |
Sample C3X output
A 32 GB SSD Single-AZ file system (small example; real deployments are larger):
aws_fsx_windows_file_system.shares
└─ Provisioned storage (SSD, Single-AZ) 32 GB-month $4.16
Monthly $4.16Optimization tips
Common ways to reduce aws_fsx_windows_file_system cost without changing the workload.
Use Single-AZ where you don't need cross-AZ durability
~50% on storage vs Multi-AZMulti-AZ roughly doubles the storage rate by maintaining a standby in another AZ. It's right for production file servers that need automatic failover; for dev/test or non-critical shares, Single-AZ halves the cost.
Right-size storage capacity
Proportional to over-provisioning avoidedFSx bills provisioned capacity, not used bytes. A file system provisioned at 1 TB that's 30% full pays for the full TB. Provision to the working set plus headroom; you can grow later.
Use HDD for throughput-oriented, latency-tolerant data
Large for HDD-suitable workloadsHDD storage is significantly cheaper per GB than SSD. For large file shares accessed sequentially rather than with low-latency random I/O, HDD cuts storage cost substantially.
Right-size throughput capacity
Per throughput tier reducedThroughput is provisioned separately and easy to over-buy. Match it to the workload's actual read/write bandwidth rather than picking a high tier 'to be safe'.
FAQ
How is FSx for Windows File Server billed?
Per GB-month of provisioned storage (SSD or HDD rate) plus provisioned throughput capacity, with Multi-AZ deployments roughly doubling the storage rate. Backups are billed separately per GB-month. You pay for provisioned capacity, not bytes used.
Does Multi-AZ double the cost?
Roughly, on storage — Multi-AZ maintains a replicated standby in a second AZ, about doubling the per-GB storage rate. It buys automatic failover and cross-AZ durability, so it's right for production but unnecessary for dev/test shares.
Should I use SSD or HDD?
SSD for general-purpose and latency-sensitive shares; HDD for large, throughput-oriented, latency-tolerant data where it's significantly cheaper per GB. Match the storage type to the access pattern.
How does c3x estimate the cost?
From storage_capacity, storage_type, and deployment_type, pricing the provisioned storage (including the Multi-AZ premium). Throughput and backups are modelled separately as usage.
Related resources
Estimate this resource in your own Terraform
Free, open source, no API key. C3X parses your Terraform and shows line-item cost for every resource, including aws_fsx_windows_file_system.