Hi Parthiban,
Load Balancing is used to distribute the Load among the Servers, so that one Server is not having the burden to execute all process, thereby resulting in slowness. Load Balanced Environment can have many structures,but generally it has a Load Balancer/Dispatcher, Central Instance, and mulptle Dialog Instances.
For details you can go through below link.
http://help.sap.com/saphelp_erp60_sp/helpdata/en/b5/e8239ef7bd494f896a84625d4b688f/content.htm
In your scenario it takes a lot of time before we realize that any of the Server is Not Working/Down or the request is not reaching to that particular server, because once we find that the Page failed to load , we refresh the page and most of the time it loades upon refresh, because the request is now going to any other Dialog Servers of the Load Balanced Environment.
To Specifically check if the Request is going to all the Severs, is that you can try pinging to all the severs one by one using cmd prompt. The one for which we are using wrong address or is down will fail.
There is separate Load Balanced Team in Every Project for maintaing them and Configuring them. Please reach out to them in case you find the same. Specifically check if the Port No is correct for the Server that is Failing, because many a times while configuration if the Port No is wrong, we are not able to figure out the Proble at that time, as we not be hitting that server, using the Common Load Balanced URL? So always Prefer checking using Direct URLs aswell.
Also, In order to check the Load Quality of every instance go to TX SMLG and Goto/Load Distribution.
If any of the Sever Node is Failing, it's better to stop that server and continue with the remaining, and then try adding the correct server again using OS Level Configuration and remove the Wrong one. Contact Basis Team for the same.
Please let me know if this helps and if you are able to find the solution.
Thanks,
Rakesh Singh