Multiple instances of merged server applications on the same machine

Hosting several 4D Server applications on the same machine is not unusual, especially for production and pre-production environments. But if your machine hosts merged server applications built with different 4D versions, which is the case if you use your pre-production server with the latest 4D version, you may encounter problems due to the shared 4D structure folder.

Let’s see how to resolve this issue.

When launched, a merged server application called “myApp” will create a structure folder:

As long as your application keeps the same structure name (to maintain automatic updates or Windows service launch command) and evolves with different 4D versions, the structure folder is the same for each merged server application.


To avoid sharing this system folder between merged server applications built with different 4D versions (as shown in the above picture), you can now set the folder name during the build application process.

A new buildApp key is at your disposal to define your own structure folder:


As a result, if you set “myApp_v18R5” for your server built with 4D v18 R5 and “myApp_v18R6” for the one with 4D v18 R6 during the build application process, you’ll have separate structure folders in the system:


Safe deployments!

• Product Owner •Damien Fuzeau has joined the 4D Product team in February 2019. As a Product Owner, he is in charge of writing user stories, then translating them to functional specifications. His job also entails making sure that the feature implementations delivered are meeting the customer needs.Damien is graduated from the University of Nantes in software engineering. He spent more than 23 years in its former company, first as developer (discovering 4D in 1997), and later as engineering manager and software architect. This company is a 4D OEM partner and deployed 4D based business softwares for thousands users, on hundreds servers. So, Damien is used to 4D development and deployment in a multi-language context.