|Managing Search / Configuring Content Search|
You can manually reindex content search, but it takes a long time and can slow performance. We don't recommend reindexing manually unless you have a specific search index problem you need to fix.
Having the application regularly update the search indexes is very handy, but rebuilding an index (via the Index Tasks tab) can be very time-consuming. You should only manually rebuild if the search index becomes corrupted or you find you're missing large amounts of content in search results. Please see these detailed instructions when manually rebuilding the search index. The rebuild processing will happen on the web app node you are accessing when you initiate the rebuild. This node sends the data to the external search service you have configured.