A monolithic application has a single code base with several multiple application packages and modules. Each module has separate business logic. This type of application has a single build for the entire application and delivered as a single deploy-able.

A huge monolithic code causes complications for developers in understanding code. Scaling of the application becomes challenging as with more copies of monolithic applications there is an increment in memory consumption, bandwidth consumption I/O traffic, and disk volume consumption.

Different application components have different resource requirements. One might be CPU intensive while the other is memory intensive. And due to the monolithic nature, we can’t scale each component individually. Loading large monolithic application code into an IDE leads to frustration as a large monolithic code-base often requires undesirable longer compile time. Also, it adds up to frustration making a single line of code change and waiting for code to recompile. It becomes more difficult to change the underlying technology, the language, and the framework because everything is tightly coupled and depends upon each other. 

Dependency Management is also a problem as any change in one module requires the entire application to be recompiled and redeployed. All components in our application talk to one database only. After some time, the database becomes huge and we have to scale the database. 

Now one application module might require a different database system with different capacity from other modules. But in monolithic architecture, we are limited to one single database. If a specific feature is not working in a single module, it could take the entire system down.

To handle the issue, the system has to be patched and rebuilt, retested, and redeployed. Take a quick pause here and when we come back, we learn about the characteristics of microservices.