For any company running a new application, it is essential to understand all the aspects of its underlying architecture. Till now, numerous debates have happened amongst experts as to whether stateful applications (with stateful architecture) are more useful than stateless applications (with stateless architecture).

In reality, the difference in the architecture of a software application defines how a user’s web browser will communicate with a web server. In the early years of the internet, the websites used to be stateless and the pages were static. With time, the websites started adopting the stateful model, resulting in better delivery of user-related information.

Before we delve further into the subject, let’s first understand the fundamental difference between stateful architecture and stateless architecture.

Stateful vs Stateless

One major function that sets a stateful application apart from a stateless one is that the latter doesn’t read or store data. It simply processes the code and other content hosted on it. Stateful applications, on the other hand, require backing storage that protects data during the service restarts. Some known examples of stateful applications include MongoDB, Cassandra, and MySQL.

A stateless application requires no changing of databases or writes, while a stateful application works across various parameters and dynamic databases. Many of these databases persist even when the app is offline or deleted.

In stateful applications, the state is recorded. By state, we mean any changeable occurrence that includes internal operations, interactions with other applications, environment variables, user-set preferences, memory content, and temporary storage. The data that such applications store depends on their types and other factors under which they operate. Usually, a stateful application is able to record your preferences, track your window size and location, and memorize the files that you have recently opened.

What Is An Effective Stateful Application?

First of all, a well-functioning stateful application should have the ability to handle long-running connections. Whether it is proxy or webservers, it should be able to hold multiple long-running connections at the same time. Not only that, but the infrastructure must be such that it can do it concurrently. For those who want a single server to serve many connections, it is the cheapest way possible.

Common Processing Differences Between Stateful And Stateless Applications

  • Stateless applications just have one function or service, while stateful applications store databases.
  • Stateless applications include web, print or CDN servers, while stateful include transactions like home banking.
  • The server in a stateless service processes requests depending on the relayed information at a time, while the server in a stateful application processes requests depending on the information relayed both previously and at the moment.
  • In a stateless application, different servers can be used to process different information, while in a stateful application, only one server is used to process all requests that are linked to the same state information.
  • Stateless applications utilize containerized microservices apps to render results. Stateful applications, on the other hand, use moving containers and remounting volumes without any application or code changes.

The Various Challenges Of Running A Stateful Application

Isolation Of Resource

Many containers available in the market still involve the best-effort approach for resource allocation. For example, CPU, storage, and memory. Such containers are suitable for stateless applications, but when it comes to stateful applications, they can prove to be disastrous, as there is a risk of loss of data and customer transactions due to unreliable performance.

Storage Space

Every stateful application needs some kind of storage, such as block devices or distributed filesystems. It can be quite challenging to determine what kind of backing storage a stateful application needs.

Management Of Data

Managing the data and service of a stateful app for a complete lifecycle is no easy task. There are a lot of things that need to be managed, including production deployment and operation and error handling.

The reason why you come across such challenges in stateful applications is due to the fact that they are built for a non-containerized setting. Organizations that want to containerize their stateful services may need to employ specific techniques and strategies to coordinate the various related instances for effective operation. This results in manual overhead requirements that can be both time-consuming and expensive.

If you are running an IT company, understanding these differences can help you advance your business. By understanding the advantages and disadvantages of stateful and stateless architecture, you can develop different types of applications to serve the users’ computing needs.