There’s been a small announcement in Azure Files that we think will be of use. Azure Files now offers storage capacity reservations. This means you commit to storage utilisation and receive a discount in return.
This capability is available on premium, hot and cool tiers. And capacity reservations are sold in units of 10TiB or 100TiB for terms of one or three years.
There is extensive documentation available from Microsoft to help you understand the pricing options for Azure Files: Understanding Azure Files billing, Optimized costs for Azure Files with reserved capacity, and Azure Files pricing.