<img src="https://learn-attachment.microsoft.com/api/attachments/259563-cost1.png?platform=QnA" alt="In this subscription I have a few web apps and one linux vm with a database. DB has only 5 or 6 users, there are no web sites. VM location is East US, users are in Brazil South. I would like to understand why the cost of bandwidth is almost 50% of total cost of this subscription - and why the cost is rising... How to investigate further? thanks! Ronaldo" />

Hi @RONALDO RADUNZ As we don't know anything about your solution and only have this screenshot... What are you doing with replication? From my understanding/imagination, I would say you have a web app that runs in "east us" and has a failover scenario established that copies all of your data and application to "be south"... so you are having a constant outgoing dataflow from US to BR... this are the costs of your subscription! You always have to pay for outgoing traffic - and that includes also traffic between regions!

azure vm bandwidth cost almost 50% of total subscription cost - how to analyze?

Accepted answer

Bjoern Peters 8,876 Reputation points

2022-11-11T13:21:51.36+00:00

Hi @RONALDO RADUNZ

As we don't know anything about your solution and only have this screenshot...

What are you doing with replication?
From my understanding/imagination, I would say you have a web app that runs in "east us" and has a failover scenario established that copies all of your data and application to "be south"... so you are having a constant outgoing dataflow from US to BR... this are the costs of your subscription!

You always have to pay for outgoing traffic - and that includes also traffic between regions!
Please sign in to rate this answer.
RONALDO RADUNZ 41 Reputation points

2022-11-11T13:35:35.847+00:00

Hi Bjoern, that is not the case, let me add a few details.
The web apps region is BR, they access the DB but there are no replication, just regular R/W DB access. Also the web apps are not heavy loads, just a few users and lots of idle time.
The VM in East US only have MySQL running, cron running a few maintenance tasks, nothing else.
One concern, however, is that some users use Power BI to access the DB. Maybe they are refreshing their tables too frequently...
How is Azure calculating the bandwidth cost? Is it directly related to the amount of data passing thru the NIC?

thanks for your help!

Bjoern Peters 8,876 Reputation points

2022-11-11T15:57:07.293+00:00

If the web app in BR is always accessing the DB in the US, and additionally, PBI runs reports on that DB... then this is the source of your costs...

Yes and No, it depends on your infrastructure... if it is the only VM in your vnet in the US... then the traffic through the NIC is your outgoing traffic, if there are more devices/services in the US region... then you might have to dive deeper into your vnet configuration... but every Byte that is leaving your services in the US to BR... that is your outgoing traffic.

Maybe this page can explain and show you how to "calculate"

37428

RONALDO RADUNZ 41 Reputation points

2022-11-11T17:44:29.017+00:00

thanks. Maybe I should stop the vm in the weekend (not sure it is possible) to see if there are other sources of traffic; one never knows...
Anyway, thanks for your help, I am very pleased with the support provided.
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.

Share via

azure vm bandwidth cost almost 50% of total subscription cost - how to analyze?

0 additional answers

Your answer