Adding a New Group and users to group just created (All Site collections and sub webs)

I needed to add a group and several users to all site collections in a farm that consisted of 4000+ site collections and 20+ terabytes. This users would be a part of an administration group that could view and manage the collections. In order to add the users I use the spfarm class.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Administration;
 
 
namespace AddUser
{
   
    class Program
    {
     
        static void Main(string[] args)
        {
            //Add all the users that will be included on the group
            string[] username =
            {   
                “laptopdev/jim”,
                “laptopdev/administrator”
                
            };
            // Get a reference to the local farm
            SPFarm oFarm = SPFarm.Local;
 
            // Loop through the services in the farm
            foreach (SPService oService in oFarm.Services)
            {
                // See if this service is a SPWebService
                if (oService is SPWebService)
                {
                    // Cast into a SPWebService
                    SPWebService oWebService = (SPWebService)oService;
 
                    // Loop through the web applications in the web service
                    foreach (SPWebApplication oWebApplication in oWebService.WebApplications)
                    {
                        foreach (SPSite oSite in oWebApplication.Sites)
                        {
                            // Get the root web object
                            SPWeb oWebRoot = oSite.RootWeb;
 
 
                            SPRoleDefinition readDef = oWebRoot.RoleDefinitions["Read"];
                            SPRoleDefinition contributeDef = oWebRoot.RoleDefinitions["Contribute"];
                            SPRoleDefinition admins2 = oWebRoot.RoleDefinitions["Full Control"];
                            SPRole admins = oWebRoot.Roles["Full Control"];
 
                            string FBARoleProviderPrefix = “CustomRoleProvider”;
 
                            string newGroupName = “Test”;
 
 
 
                            foreach (SPGroup spGroup in oWebRoot.Groups)
                            {
                                //if the group we want to add does not already exist, create it at the top level and make
                                //the owner the top level owners group.
                                if (!oWebRoot.SiteGroups.Xml.Contains(string.Format(”Name=\”{0}\”", newGroupName)))
                                    oWebRoot.SiteGroups.Add(newGroupName, oWebRoot.SiteAdministrators[0], null, “This is for administrator for all sites” + newGroupName);
 
                            }
 
                            try
                            {
                             
                                SPGroup newGroup = oWebRoot.SiteGroups[newGroupName];
                              
                                newGroup.AllowMembersEditMembership = true;
                                SPRoleAssignment spRoleAssignment = new SPRoleAssignment(newGroup);
                                SPRoleDefinition role = oWebRoot.RoleDefinitions["Full Control"];
                                spRoleAssignment.RoleDefinitionBindings.Add(role);
                                oWebRoot.RoleAssignments.Add(spRoleAssignment);
                                oWebRoot.Update();
                                foreach (string UserName in username)
                                {
                                    SPUser oUser = oWebRoot.AllUsers[UserName];
                                    newGroup.AddUser(oUser);
                                    newGroup.Update();
                                }
 
 
 
                                // Be sure to dispose the SPSite and SPWeb objects for memory cleanup
                                oWebRoot.Dispose();
                                oSite.Dispose();
                            }
                            catch { }
 
 
                            //Do the same for all the subsites under a site collection.
                            //Add Full Control to the group
                            foreach (SPWeb subWeb in oWebRoot.Webs)
                            {
                                SPGroup newGroupSubWeb = oWebRoot.SiteGroups[newGroupName];
                                SPRoleAssignment spRoleAssignmentSubWeb = new SPRoleAssignment(newGroupSubWeb);
                                SPRoleDefinition roleSubWeb = oWebRoot.RoleDefinitions["Full Control"];
                                spRoleAssignmentSubWeb.RoleDefinitionBindings.Add(roleSubWeb);
                                subWeb.RoleAssignments.Add(spRoleAssignmentSubWeb);
                                subWeb.Update();
                            }
 
                        }
                    }
                }
            }
 
        }
       
 
    }