Azure Data Transfer Costs: Everything You Need To Know
Cloud costs quickly become a concern when your IT infrastructure starts to scale. You may plan your cloud consumption, estimate cloud budget, but monthly bills often come with expensive surprises. This usually happens because data transfer charges are overlooked and remain unaccounted for during resource planning.
In this article, we will understand every little detail of Azure data transfer, costs associated with various data transfer scenarios, the hidden extras that you could have otherwise missed, and ways to lower these charges.
What Is Azure Data Transfer? How Do You Get Charged For It?
Data Transfer or bandwidth (as often mentioned by Azure) is the process of moving data in and out of Azure data centers and transferring data across different data centers. Other data transmissions to and from data centers are facilitated by ExpressRoute connections, Content Delivery Network (CDN), or Peering.
Azure does not charge for the inbound flow of data, i.e., incoming traffic from the internet. However, anything and everything that leaves your Azure’s network incurs a data egress cost, charged on a per GB basis.
Types of Azure Data Transfer Scenarios — Demystifying The Hidden Charges
In recent years, Microsoft has stretched the pricing options for outbound data transfers (now commonly referred to as data egress) depending on traffic origins, availability zones, regions, services, and so on. So let’s explore these scenarios:
1. Data Transfer within Virtual Network (VNET)
When you move data or deploy resources within the same VNET, Azure doesn’t charge you anything for data transfer. But, your data transfers are free only if the services (where data transmission occurs) are located in the same subnet, or the transfer happens from one subnet to another inside the same VNET.
2. VNET Peering
Virtual Network Peering or VNET Peering establishes a connection between virtual networks that enables you to route traffic across these VNETs through private IPv4 addresses. Data ingress and egress are chargeable at both ends of VNETs peered together.
a. Pricing of VNET Peering within the same Azure Region
Data transferred between two VNETs in the same region is known as regional VNET peering. The charge that applies for inbound data transfer is $0.01 per GB, while outbound data transfer costs $0.01 per GB in this case.
b. Pricing of VNET Peering across different Azure Regions
When VNET peering is established between virtual networks located in different regions, we call it global VNET peering. The prices of global VNET peering depends on the zonal structure. So, you will be charged based on the data transfer rates applicable to a particular zone where your VNETs are provisioned.
Data Transfer Type | Zone 1 | Zone 2 | Zone 3 | US Gov |
Inbound Data Transfer | $0.035 per GB | $0.09 per GB | $0.16 per GB | $0.044 per GB |
Outbound Data Transfer | $0.035 per GB | $0.09 per GB | $0.16 per GB | $0.044 per GB |
3. Data Transfer between Azure Availability Zones
Azure data transfer within the same availability zone is free of charge, while data transfer between two different availability zones now incurs a cost of $0.01 per GB.
The data transported across different availability zones incurs charges, even if you deploy them inside the same VNET. Besides, you will be charged for both ingress and egress data traffic in this scenario.
4. Data Transfer across Azure Regions
As mentioned earlier, incoming data traffic or data communicating between Azure services within the same region incur no charges. However, charges start to kick in when data is moved across different Azure regions. These charges depend on the amount of data being transmitted and on the zone from where the traffic is originating. For example, if you transfer data between regions within North America (intra-continental data transfer), you will be charged at a $0.02 per GB rate.
Another data transfer scenario to consider is the ExpressRoute service that provides hybrid connections between Azure data centers and your on-premise infrastructure (or in a colocation environment) through ExpressRoute Circuits and ExpressRoute Gateways. You can explore pricing options for ExpressRoute here.
Optimization of Data Egress Costs
To reduce and control superfluous egress costs, you need to make your architectural choices carefully. One of the key strategies to minimize outbound data transfer costs is gaining a deeper understanding of your architecture and optimizing the data outflow corridors in your Azure network. Since charges of transporting data vary based on the location of the traffic source and the destination where data lands up, different data transfer rates apply.
Implementing the following best practices helps lower such creeping costs:
- Deployment of cloud resources in regions that charge minimal or zero data transfer cost unless mandated by certain security policies or compliance obligations.
- Limit the cross-zone and cross-region data transfers to keep the budget in check. Bandwidth prices shoot up quickly when you move data across different availability zones, regions, or countries. Ensure that every data transfer is reviewed, approved, and purposeful, i.e., only necessary data should be deployed to a geographical area closest to the user base or operation center.
- When you are using different Azure services in different regions in architecture, data transfers cost you money. Therefore, it’s a best practice to keep the data in the same region.
- Consider optimizing the architecture of your applications to minimize the traveling path of data.
- Using ExpressRoute connections for transferring data might turn out to be cost-effective in cases where VPN data egress charges are higher.
- Do not forget to compress and deduplicate your data (using incremental synchronization) before egressing them from Azure data centers. Also, delete or archive the data you don’t need anymore to save costs.
In Conclusion:
When you are running a business and operating your IT infrastructure on cloud, data transfer costs can quickly spiral out of control. As volumes of data are transferred to and from data centers, you need to have complete visibility into your Azure ecosystem.
With CloudMonitor’s automated cost monitoring capabilities and smart recommendations for optimizing costs, you can manage your egress costs and keep an eye on the frequency of data transfers. In addition, its active and custom alerts detect sudden increases in the set budget and notify you about the unusual spending to avoid bill-shocks at month’s end.
Rodney Joyce
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