Bulk move of Workitems and Defects from one server to another

Anil, there are some limitations on work item export and import. You will not be able to copy all the information AFAIK. I think you will lose history, approvals, attachments and links. Here are some documents which should help:

I will assume you are using RTC 6.0.3. The steps should be similar if you are on a different version.

Exporting work items
https://www.ibm.com/support/knowledgecenter/en/SSCP65_6.0.3/com.ibm.team.workitem.doc/topics/t_exporting_work_items.html

Copying work items between repositories using CSV export and import
https://jazz.net/library/article/522

Here are some links:

[CCM] Move a project area between repositories                         
https://jazz.net/forum/questions/38129/how-to-move-a-project-area-to-another-rtc-server                                                        
                                                                       
Project move from one server to a new one                              
https://jazz.net/forum/questions/180922/project-move-from-one-server-to-a-new-one                                                              
                                                                       
Is it possible to move workitems from one Project Area (on server A) to
another Project Area (on server b)                                     
https://jazz.net/forum/questions/134174/is-it-possible-to-move-workitems-from-one-project-area-on-server-a-to-another-project-area-on-server-b

If both servers are in the same repository, you can copy a workitem from one project area to the other without loss, however, I believe you can only copy one work item at a time. Open the workitem and select the option to copy or move to a different project area.

https://jazz.net/jazz/web/projects/Rational%20Team%20Concert%20%28SAFe%29#action=com.ibm.team.workitem.viewWorkItem&id=169824

You can copy widgets over from one dashboard to another, but otherwise you need to recreate the dashboards too.
https://www.ibm.com/support/knowledgecenter/en/SSCP65_6.0.3/com.ibm.jazz.dashboard.doc/topics/t_move_viewlet.html

Maybe this is a start.