So, the decision has been made. It’s with great excitement that you are migrating to Azure. You’re all set, you’ve got your colleagues on board, you’re working with a great partner and it’s all systems go… or is it? Just wait one minute. Before you hit GO, there’s something you need to think about… Latency.



Latency, in computing terms, is the delay before a transfer of data begins following an instruction for its transfer. So it is a measure of delay. What you need to think about before migrating to the Cloud is specifically network latency.


In a network, latency measures the time it takes for some data to get to its destination across the network.  It is generally measured as a round trip i.e. the time taken for information to get to its destination and back again.  The round trip delay is an important measure because a computer that uses a TCP/IP network sends a limited amount of data to its destination and then waits for an acknowledgement to come back before sending any more.



Since latency refers to the length of time it takes for data to travel to its destination and back again, it’s easy to see how the speed of that trip will impact on the performance of the network. Latency drives throughput.  You can have the best hardware in place and Azure set to go but if you’re getting a high latency then you’re not going to get the performance you want.


Of course there are a variety of factors to consider when you’re choosing a datacentre and latency is just one of them, but get it wrong and you’ll always struggle with poor performance. Fortunately someone’s thought of this before.



Currently Microsoft Azure is available in 50 regions worldwide, and 140 countries, so that’s a lot of choice in terms of where to place your data. This is where a speed test tool for Azure comes in very handy. This tool allows you to test network latencies and speed to Azure data centres from different countries and locations.  Along with finding the closest Data Centre to your location, it tests the storage latency to Azure as well as upload and download speeds.



Remember that latency is not the only cause of poor application performance.  In the majority of cases poor performance is caused by issues with the application, database or infrastructure, so take care to look at the whole picture. Take a look at our posts on performance and follow us on LinkedIn to keep up to date with news and industry insights.