What is AutoScaling? Everything You Need To Know

middleware team

MW Team

August 25, 2021

What is AutoScaling? Everything You Need To Know

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If an organization or business wants to achieve significant growth, its websites, applications, or online platforms should be able to handle the corresponding increase in traffic and use. Every application draws the necessary computing power from a server or group of servers - also called a server farm - on which the application is hosted. Each server possesses limited computing capacity, so what happens when the app needs more power than is currently available?

'Scaling up' is the process of increasing the computing resources made available to an app that is seeing high volumes in traffic, thereby addressing the need for more computing power. The other side of the coin is 'scaling down', which refers to the reduction in the computing resources allotted to a particular web resource due to low traffic, thereby bringing down power and energy consumption. 

Now, what if you could have your app hosted on a server that is capable of autoscaling your computing power, i.e., can 'scale up' the computing resources made available to your app when there is a spike or rise in web traffic and alternatively 'scale down' the resources when traffic levels are low. Autoscaling aims to take advantage of the wonders of cloud computing in order to scale your app to meet all potential levels of server load, high or low. 

In recent years, autoscaling has been widely accepted for its versatility, flexibility, and cost-effectiveness. Some of the world's most popular websites, such as Netflix, have opted for autoscaling support to enable them to meet the growing and ever-changing demands of their consumers. Some of the most popular cloud computing services today that offer autoscaling services are Amazon Web Services, Microsoft's Windows Azure, and Oracle Cloud.

Read on to find out more about autoscaling and why it might not always be the flawless strategy it seems to be. 

Why autoscaling is an attractive option


Any business, big or small, can reap the various benefits of autoscaling services. The following are the key advantages that autoscaling offers.

  • Lower energy consumption: With the application of autoscaling to a website, servers will be able to go to sleep during periods of low traffic. This significantly lowers the amount of electricity that a company uses in cases where its application is hosted on its own server infrastructure.
  • Cost-effective: Most cloud computing service providers charge based on server usage and not capacity, which translates to lower server costs when compared to paying for the maximum required capacity irrespective of usage. This is particularly beneficial for organizations that see massive fluctuations in web traffic, such as online retail outlets, travel booking applications during holiday seasons, and so on. 
  • Better load management: Autoscaling aids in effective server load management since servers can be put to use during periods of low traffic in order to complete computing tasks that are not time-sensitive. This is possible since autoscaling significantly frees up server space when there is less traffic.
  • Protection from website/app failures: Autoscaling services such as the one provided by Amazon Web Services ensures that unhealthy instances are replaced promptly. This, to an extent, offers limited protection to an app from network, application, and hardware failures.
  • Dependability: When server loads are highly erratic and unpredictable, such as in the case of eCommerce websites or video streaming services, autoscaling ensures preparedness to handle the varying server demands, making it a dependable option. Server failure is often a very expensive affair that is capable of causing tremendous losses to the organization. In 2018, J.Crew's server failure on Black Friday cost them a whopping $700,000 in sales. Amazon India suffered a similar outage in May 2021, with the website being down for a couple of hours which affected sales. 

Autoscaling is not as easy as it sounds

Autoscaling today is a powerful, sophisticated and useful computing feature that helps millions of websites/apps manage their server loads. However, similar to the problems that traditional scaling up poses, several hurdles need to be overcome to achieve autoscaling as well. Here are four overarching reasons why autoscaling might be difficult to optimize and apply, especially in the cases of large servers with huge volumes of information.

1. Searching for information becomes difficult: Imagine an eCommerce website that has a database with over a million names and contacts of its customers. Irrespective of measures taken to organize this data, scouring this massive data set for information is not an easy task. With autoscaling, however, this information needs to be made available across the additional servers put to use at any point in time which makes it a significant problem to address. 

2. Consistency is hard to achieve:  In the case of the eCommerce website opting for autoscaling services, another significant hurdle is achieving consistency. For example, at times of flash sales, product availability data is constantly being updated and these changes should be made available to all users on the platform to ensure that no individual is able to place an order for a product that is no longer available. Ensuring consistency of information and data in such situations, especially when server load is high, is no mean task. This can be termed a consistency problem.

3. Concurrent usage increases server demands: With the same example as above, imagine each of the million users is trying to log into the eCommerce website in order to purchase one particular product. Although unlikely, it is the kind of situation a server needs to be ready for. Each of these users must be given access to the data and information on the servers simultaneously and this is a major challenge that any autoscaling attempt must overcome. 

4. Maintenance of speed: With scaling up and server addition, especially if huge swathes of information are involved, there is bound to be an impact on the speed with which these computing resources can be deployed in order to make information available to users on the application or website. 

Why cloud service providers are reluctant to offer native autoscaling support

Apart from the sheer amount of computing resources and expertise required to tackle the challenges of autoscaling and provide a satisfactory experience to customers, the main reason that native autoscaling support is not provided by most cloud service providers is that the costs involved are very high.

1. Physical server costs: Cloud-based hosting services that offer autoscaling almost always use horizontal autoscaling to achieve the desired result. This entails the deployment of additional servers or machines to the existing resource pool as compared to vertical autoscaling which refers to upgrading the existing servers and machines. A good example of vertical autoscaling would be the increasing RAM capacity in an existing machine. Irrespective of the means used to achieve autoscaling, the expenses that a cloud service provider incurs are high. 

2. Investment in manpower: In order to ensure autoscaling is managed efficiently, a dedicated team of experts is needed to monitor and oversee the autoscaling process, especially in cases of websites that see extremely large volumes of traffic. A good example where a website would need such support would be an eCommerce website such as Shopify or Amazon during the festive sale season; comparable to Black Friday sales in the United States. Therefore, not all cloud service providers are willing to make the substantial investment required to build a team that is capable of supporting autoscaling natively on their platforms. 

The verdict

Autoscaling is an increasingly popular web hosting feature that is undoubtedly here to stay. With enormous dedication and financial backing to the technology and strategy, tech giants like Amazon have ensured that consumers now have access to reliable autoscaling features and are constantly working to improve the experience that they offer. 

An organization that is interested in making the most of autoscaling may choose either vertical or horizontal autoscaling options. Right off the bat, vertical autoscaling is not ideal for web applications or resources with thousands of users since there are several architectural limitations to upgrading existing servers that affect availability. On the other hand, horizontal autoscaling is more than capable of ensuring continued availability. This is because user sessions are not restricted to one localized server, but are spread out seamlessly across a server pool that can be either expanded or shrunk based on the ever-changing requirements of the web application.

Despite the investment required and challenges to be overcome, autoscaling offers several short-term and long-term benefits to organizations. Therefore, if an organization is looking to scale up its operations and web resources, autoscaling is more often than not, the best available option today. 

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