What should be the cpu and Ram requirements? the workflow is simple and involves parallel editing of excel.
If you are talking about near 150 concurrent users, you should first think on Sharepoint 2010 Capacity planing and plan for performance.
Take a look at
Download Capacity planning for Microsoft SharePoint Server 2010 from Official Microsoft Download Center
Plan for performance and capacity management in SharePoint Server 2013
Also take a look at the Workflow limits section on this Pamela Denchfield 's document >>> SharePoint limits related to Nintex Workflow
Personally, on a bank, I built processes with +100 running instances of workflows on a same list. I did many POCs so as to adapt my need to the current capacity.
How will be your concurrency? Will 150 users authenticated at the same time upload 150 documents?
Consider building a "starter workflow" that will start your main workflow with some "wait" logic so as not to have many instances at the same time.
My scenario is also for bank internal departmental usage.
The concurrency is that at busy period, 150 concurrent users are supported. Assume each of those 150 concurrent users (1) upload and start Nintex parallel approval workflow; and (2) download several excel from SharePoint library.
My current infrastructure is:
1) One WFE server: 4 CPU vCore, 12G RAM
2) One Database server: 2CPU vCore, 20G RAM
Adding new server is not preferred because of license cost. Do I need more resources?
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