Ruby on Rails

How to Scale my Ruby on Rails App (the right way) [2022]

Do you know how to scale your Ruby on Rails App?

Do you know 2022 is considered the era of mobile development?

The ruby on rails app development is excellent for sophisticated user experience in the eCommerce field. The success in gaining more and more customers is not the endpoint. Managing the streamline of customers is the ultimate solution for running a successful app. Scaling the ruby on rails app technically prepares it for customers’ ease. 

But, how and why does the scalability of the ruby on rails app matter? How you can scale your ruby on rails app for wide audience reach. Continue reading our complete guide to finding the best solution. 

What does Ruby on Rails scalability means?

Scaling ruby on rails app is an easy phenomenon to understand. In simple words, the scalability of the ruby on rails app refers to handling massive traffic, deploying additional servers, and generating more requests per minute. 

The deal is:

The ruby on rails apps are easily scalable. But for scaling apps, the system architecture is of primary concern. Let’s clear it with an example. 

Suppose, your ruby on rails app is designed for managing 1000 customers. But with time, your application grows and customers increase. Now, the single server cannot handle your massive user requests. The system becomes unresponsive, and the server may crack. That’s why the entire architecture for the ruby on rails app needs scalability. 

A number of popular platforms and apps are scaling their ruby on rails apps for the successful generation of user requests. You might first consider Shopify-they are using Rails. 

But don’t worry about how to scale the ruby on rails app and address the issues. Ruby and Rails are open source community-guided platforms with numerous useful tools. 

Before digging deep into scaling tips, let’s take a close look at two approaches for scaling apps. 

Vertical Scalability

Vertical scaling is the simplest and easiest method. It involves the utilization of additional servers to the application. The upgradation of the slow database is easily achievable with vertical scaling. Sow databases speed up with better server inclusion. 

Summing up, you can enjoy the following benefits with vertical scalability:

  • Enhanced RAM
  • Increased RPMs
  • Upgraded server and database

All these steps ultimately empower your app but for a limited time. With an increase in traffic, you can encounter technical impossibilities. 

There are also certain limitations with vertical scalability. It can be challenging to scale the ruby on rails app on cloud usage. 

Like, if you want to implement (VPA) Vertical Pod Autoscaling on Kubernetes, you can observe various limitations. So, it is better to turn to horizontal scaling to avoid these limitations and issues. 

Horizontal scalability

Horizontal scaling is a step further future-proof technique for scaling ruby on rails app. It differs from vertical scaling in many features. 

Horizontal scaling is the conversion of your application to three-tier architecture involving:

  • Server and load balancers like Nginx
  • Rails app instances for better communication
  • Database instances for both local and cloud-based 

Another plus point for horizontal scaling is the use of thread-safe languages. The main idea of horizontal scaling circulates around reducing and equating the lesser machine load for outstanding performance. But you should know the criteria for selecting the right database instances, better load balancer, and optimal web servers. 

Load Balancer-Nginx

Load balancers act as the key structural elements for scaling out app architecture. Nginx is one of the most commonly used software servers for Rails applications. It is termed and placed on a single machine as a load balancer and reverse-proxy. Nginx can server faster under loads because it needs low computing power for normal functioning. 

Nginx mainly serves to distribute the load among different servers. The server configuration is properly allocated so the request goes to the appropriate computer. Nginx server sends the first request to the first machine, the second request to the second machine, and further on. If you have three machines with Rails instances, then the fourth request will go to the first machine. 

App Instances

Next step for scaling out your RoR application is the communication between the different application servers. App instances are the places where the rails workload is placed. 

App servers conduct seamless communication between the web servers. Thus, it increases the number of requests generated and processed per second. Another important benefit is an app server can handle various app instances. 

Rack, a special interface that handles communication between the application and the server is termed an application server. Various application servers are used for ruby on rails applications. The most popular application servers are:

  • Unicorn
  • Puma
  • Phusion Passenger

Application servers allow the application to deal with the user requests elegantly. But you should ensure smooth communication between the app and web servers.  

Yet the right selection of app instances is also crucial. You can consider the following points for selecting the right app instances. 

  1. For regulating pod size, prefer having four variables for min/max CPU and memory
  2. Use the formula [minimum requirement + 20%] for limiting resources
  3. For scaling matrices, use average CPU utilization and memory
  4. Focus on timing. Clusters can take up to 12 minutes for scaling on Kubernetes

If you don’t want to make guesswork for scaling the features for the RoR app. Use the Engine Yard-all-in-one pack for scaling with predictive features. 

Bonus Tip:

Before scaling the app instances, pay attention to the request queue. Check the request queue time. This will save your money, if your queue is empty you are wasting time in scaling. 

Database Scaling

Another way to scale your ruby on rails application is transferring your databases to separate servers. Dealing with the database is necessary for increasing user requests and segregating user data. Because the query doesn’t need to move to various places where data is stored. It will directly go to the database for collecting the information. 

All the techniques are performed to reduce the load on the database. Or you can also use a database tier for scaling your application. 

The database tier can be a single server using a database allocated to various app instances. The tier can also consist of various machines each running the databases. You can use database replication to update data across all the databases. When you update data in the database, it informs all others about the changes. It is the multi-master relationship between databases as a standard procedure. 

What happens when the Ruby on Rails App is not scaled?

Definitely, many questions arise in your mind. You might want to know why you should scale your ruby on rails app. How is it necessary for your business? The following point will highlight the importance of scaling the ruby on rails app. 

If you don’t scale your ruby on rail app:

  • Application will slowdown
  • Can even crash
  • Customers can leave
  • Dissatisfied reviews

All these facts need improvements in scaling. 

What Common Issues Need Scaling?

 Here are the common issues that need scaling.

  • Over-engineered app structure
  • Suboptimal database setup
  • Insufficient server bandwidth
  • Low caching speed
  • Improper indexing 
  • Inefficient logging or monitoring

What Obstacles can you face while scaling the app? 

RoR offers developers many conveniences like the integration of clean and modular code. Despite the issues that need scaling, some problems can arise because of improper scaling. 

The major problem lies with the application architecture. The improper implementation may lead to delays in user requests. Also, the server bandwidth affects the scalability. If your app generates more customers, it will impart a strain on the server capacity. The result will be a reduction in the app speed. 

You need to be careful and keep a meticulous eye on every parameter while scaling the app. 

5 tips to scale my Ruby on Rails App this year

If you don’t want to lose your reputation and money, scaling the ruby on rails app is the ultimate solution. But wait:

You need some pro tips for smooth and error-free scaling. 

Don’t worry, sit around here and get the additional tips for scaling the ruby on rails app. These tips will help you a lot to avoid the common issues in scaling your app. 

1. Duplicate your infrastructure

You can take multiple steps to expand your infrastructure for handling user requests. 

The very first tip is not to store all data in a single database. Avail of different databases for saving your data. It might be costly, but it simplifies the process of scaling the application. 

You can use two basic approaches for duplicating your infrastructure. Multi-master and Multi-slave replication are used for replicating databases. In master-slave replication, the primary data is stored in the main database. The remaining database receives an update when the main database acts. 

Or you can deploy another technique of service-oriented architecture for scaling. It is used by many companies for their campaigns like Shopify and Facebook. This technique is easier and cost-effective to apply. The extensively used application part is shifted to a separate server as a standalone application. Thus, it decreases the load on the main server. 

2. Choose databases correctly

Database selection is the most important step for scaling. Slow database queries, bad caching, and inefficient database indexing can lead your running app to the trash. Try to separate the database from other servers while scaling the app. 

Or simply, transfer the database to a separate server used by all the app instances. Scaling the app with the proper database significantly reduces the time for queries. Because in such a case, the query does not go to several databases that hold data. It will collect data from the particular repository. 

If you have a high data record, the database must be efficient to save it and send back to the customer quickly. 

Pro tip:

You can set up dedicated MySQL and PostgreSQL for your databases. But for great data storage, PostgreSQL and MongoDB are preferred. Keep them clean and ensure the optimal instance size. AWS RDC gives you freedom of selection from 18 types of database instances. 

Going deep into scaling the database, look for missing database indices and inappropriate code. Whenever you made great integration, check the slow query log. You can scrub your database for the indices that are not used for a long time. 

3. Recognise when you are reaching your limit

Focus on scaling the storage and analysis of a large amount of unstructured data. Know the scalability limitations, regardless of the file system you are using. Like if you have heavy data reporting, try to use the main database for reporting rather than production databases. 

4. Getting the most out of caching

You can easily enhance the database performance with the database caching implementation. Although caching is not directly related to scalability. But it is a great step to increase the speed of data delivery to the client. 

It is best to use Ajax libraries like jQuery. Because it allows the data to browse on demand. To cache HTTP responses at your site, you can use gateway proxy caches. Or you can also learn how to use etags and expiration. 

Also, you can benefit from the Rail’s built-in caching feature. It automatically converts the results of user queries to cache. It’s a huge benefit to use the native Rails caching feature. 

Implementing the caching process helps to speed up the slow and buffering queries and improve data availability. But before using, investigate and deploy the best strategy. 

You can use any of the following strategies. 

  • Low-level caching-work for every cache to speed up queries 
  • Redis cache store- provides you 512Mb memory, data replication, and key storage 
  • Memcache- a great option to cache results pulled from your database. Suitable for multi-thread architecture. 

5. Manages external dependencies and reduces their use

Check for your external dependencies including your ads serving network and RSS feeds. Some of these services don’t promote and support the increasing user requests. If this happens, then make sure to have a fallback strategy. 


Deploying the ruby on rails application is not the perfect solution to every need. With the increasing technology and number of customers, scaling the ruby on rails app is the best option. 

Scaling depends on various factors and your project type. Different methods and techniques make it easy to scale your RoR application. In short, scaling is the balancing act of best app instances, optimal resources, and a careful container approach. But still, several issues need to be addressed. You can scale your application, but it is worth considering answering the following questions:

  1. What’s your motive: do you want your app running for real users or want to scale for an imaginary future?
  2. What tools are best for scaling your ruby on rails application?
  3. Is there a single approach for scaling the app?