oh no!! get crazy with my lab server for the index and search problem!! after few day on testing and google , i able to understand some concept. Just want to keep the record here for future reference.
what is search server ? as i understand is copy the index file from index server and keep and search server, when user do the search query.
How to reset the search server propagation file ? is simple step , stop the office at central admin -> operation -> services on server -> office SharePoint Server Search ( on top select the server you want to reset)--> click on the Action Stop --> go to the index file delete the folder --> click the action start the search service. At this moment the search server will pull the propagation from the index server.
what is index server ? Index server is the server to do pull the indexing data from SQL and keep it at index server then propagation to all search server.
how to reset the index ? go to SSP --> Search administration --> Reset all crawled content --> click Reset Now. After reset all the index will become Zero (nothing) , so you need to start the Crawl. Go to Content sources ->click on the Start full Crawl under the Local Office SharePoint Server sites. then waiting the crawl, if you have alot content will take up few day to complete it.
yeah..this is what i want to share about the index and search .. :) . if you want to find specify file have crawl or not you can check onw the Crawl log.