This is a very interesting question. We have a use case too in which we are estimating similar numbers for a different custom DocType which is a price database for electronic components. While your numbers seem high to you, this is really not high volume of data, that would be terabytes in a MariaDB instance.
Does ERPNext support such a high volume of data processing?
One problem that we have seen throughout the system is indexes missing which causes some DocTypes to load very slowly. These are because some of these DocTypes just haven’t been designed for big data. With Sales and Purchase Orders as well as the transactions this should not be the case. In any way these are easily fixable as the system scales. I hope the foundation or Frappe will dedicate some resource into optimizing the database design.
Having said that, these are really pretty minor and easily fixable. MariaDB can absolutely handle data like this and the framework can either handle it or can be adjusted if needed.
Does ERPNext support 50-100 concurrent users and how good ERPNext is in concurrent processing?
50-100 users isn’t much. The system handles that easily. Tasks are properly queued in the system.
Would ERPNext be able to process and generate various transaction reports?
There are plenty of reports already available out of the box, you can WYSIWYG create custom reports yourself or if they are really tricky you can code them in Python.
Is it possible to split data year-wise?
What does that mean?
Has anyone implemented ERPNext for such a high volume business? What challenges did you face and what are changes did you make?
We are on track of implementing it for a similar load and we are not worried.
What infrastructure would be required to run application seamlessly?
Go with the ERPNext Pricing 2022 800 USD / Month medium plan and have Frappe deal with the Database and help you when performance issues arrise.
If you insist on self-hosting, have an average gaming PC like a I7 or Ryzen with Ubuntu Server installed.16GB Ram on a RAID-1 SSD with 128GB for Frappe and consider an internal HDD for backups.
What are the points we have to keep in mind while doing implementation?
Fine-tuning your server and tracking the performance of your MariaDB server will be essential to success here. You are probably best to get professional help with this by having Frappe manage that for you, otherwise you will need to have someone manage that for you since you are moving big data.
Hope this helps!