I have a web application with around 40 site collections each with its own content database.now i want to configure a search service that would retrieve search result from all of the site collections. How do i go about it? Also,is it possible that search happens in a particular list/library instead of searching all the lists and libraries??
I assume you are working with SharePoint 2013. For the first question to configure all site collection for search you need to create a content source under which you will specify the content to be crawled from. To create a content source you can this link
And for second question to search happens in a particular list/library instead of all list and libraries.
There are two way to do so:-
First one is creating a result source and specifying the query to return content from specific list only. For creating a content source with query
And the second option is to uncheck the option appear in search option in list setting --> Adnvance setting -->
Allow items from this list to appear in search results?