Size a Filestore instance against its tier minimum and capacity step, and see the throughput and IOPS you get.
Filestore performance is a function of provisioned capacity, so the only way to buy more throughput or IOPS is to buy more TiB — and every tier has a minimum plus a step size that rounds your request upward. That means a 1.1 TiB requirement on a 256 GiB step is billed at 1.25 TiB. Because throughput scales with size, teams frequently over-provision Filestore for performance and then treat the spare capacity as waste, when the honest framing is that they are paying for MiB/s. Confirm the per-GiB price for your tier and region in the Google Cloud pricing calculator, as regional costs noticeably more than zonal.
Filestore Capacity
billed capacity = max(tier minimum, requested rounded up to the capacity step); throughput = billed TiB × MiB/s per TiB; cost = billed GiB × tier price + backup GiB × backup price.
billed capacity = max(tier minimum, requested rounded up to the capacity step); throughput = billed TiB × MiB/s per TiB; cost = billed GiB × tier price + backup GiB × backup price. Filestore performance is a function of provisioned capacity, so the only way to buy more throughput or IOPS is to buy more TiB — and every tier has a minimum plus a step size that rounds your request upward. That means a 1.1 TiB requirement on a 256 GiB step is billed at 1.25 TiB.
Because throughput scales with size, teams frequently over-provision Filestore for performance and then treat the spare capacity as waste, when the honest framing is that they are paying for MiB/s. Confirm the per-GiB price for your tier and region in the Google Cloud pricing calculator, as regional costs noticeably more than zonal.
This calculator takes 11 inputs: Capacity you actually need, Service tier, Basic HDD price per GiB, Basic SSD price per GiB, Zonal price per GiB, Regional price per GiB, Read throughput per TiB, IOPS per TiB, Backup data retained, Backup price per GiB, NFS clients mounting the share. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
No. Capacity can be increased in place but not reduced, so the safe pattern is to start near the tier minimum and grow, rather than provisioning for a year of forecast growth on day one.