It depends on what the project is, if the company has the intellectual property rights of the project, there should be less overtime, if it is an outsourcing service nature of the overtime is more.
System operation and maintenance engineers are also known as operation and maintenance development engineers in China, responsible for maintaining and ensuring the high availability of the entire service, while constantly optimizing the system architecture, improving the deployment efficiency, optimizing the utilization of resources to improve the overall ROI.
Operation and maintenance engineers are responsible for the stability of the service, to ensure that the service can be 24 hours without interruption to provide services for the user.