If there is a daily update of the files (~2-3 TB of data uploaded daily), is this considered as Ingress traffic that is free of charge?
Yes, any uploaded files would be ingress traffic and not charged outbound data transfer fees. You would still be charged for the transaction prices.
When there are files downloaded or extracted daily at the rate of (1-2 TB of data downloaded or copied over to another OnPremise server by a 3rd party apps), is this considered as Egress traffic which is charged per MB?
If the data is not cached locally on the File Server it will need to be recalled from Azure Files. This would count as outbound/egress traffic and will be charged accordingly.
What is the cost associated with the Azure File server running File Sync from the OnPremise server?
Sync servers are charged at $5 per month. Sync uses file operations to sync your data to the cloud and other servers, and you will be billed for any operations that are generated in the sync process. The number of file operations generated and the access costs scale with the number of file changes on the server and the number of servers that need to be kept in sync.
For more information you can refer to the planning document. You can also utilize the pricing calculator to get a better idea of the costs. If you have further questions related to billing you can create a free support request with out billing team. They should be able to best assist with any questions regarding billing and costs.
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