Search is indeed a mission critical component in SharePoint 2013 and it’s very important that it functions properly so that you get the desired results. As we all know, the search results and their relevancy is directly proportional to how often your content sources are crawled and what sort of crawling you’re running in your SharePoint farm (i.e. full crawl, incremental crawl and continuous crawl). So, in this post I’m not going to discuss about the different type of search crawls or the SharePoint 2013 search architecture, perhaps I would be discussing on when and under what circumstances should a SharePoint administrator perform a full search crawl. The reason for me picking up this topic is because I see a lot of misconception among SharePoint administrators in understanding when the Search full crawl has to be performed. For the most part, I’ve seen many folks turning on full crawl when it’s not required at all and before doing so we need to understand that turning on Search full crawl is going to consume a lot of your server’s resource and at worst case it could even make your SharePoint farm go to an unresponsive state and hence it’s very important that we do this only when it’s required.
Alright, let’s get into the details ….
Listed below are the reasons why and under what circumstances should a SharePoint farm Administrator perform a full search crawl:
1.You just created a new Search Service application and the default content source (i.e. Local SharePoint sites) that gets created along with the newly created Search service application hasn’t been crawled yet.
2. You recently added a new content source and it hasn’t been crawled yet (Note: This is applicable for all the types of content sources (i.e. Local SharePoint sites, File shares, Exchange public folders and External line of business data)
3.When there has been, a change made to the existing content source (meaning, when you’re trying to edit the existing content source for making some changes)
4.When you’re patching your SharePoint 2013 farm by installing a Cumulative update, Service packs and hot-fixes etc. For some reason I see a lot dilemma on this specific point because it brings up a question on why should a full crawl be performed post the patching .The reason for this is really simple , if you read my article on patching a SharePoint farm you would notice that I’ve mentioned a step where you need to suspend the search crawl before patching your farm and the reason for mentioning that is because it’s quite possible that when you check the crawling schedule before patching you farm there may not be any instance of crawl running. However, if a crawl is triggered by schedule which occurs during the installation, the search application may crash or lead to inadvertent results. In worst case, you might end up rebuilding the entire search application. Hence, as a best practice it’s very important that you suspend the search service application before patching your farm and once you’re done with patching your farm please go ahead and resume it and run a full crawl.
5.When changes have been made to managed properties in search. A full crawl of all affected content sources is required for the new or changed managed property to take effect.
6.If you want to detect security changes that were made to local groups on a file share after the last full crawl of the file share
7.When the incremental crawl keeps failing continuously. If an incremental crawl fails many consecutive times for any content, the system removes the affected content from the search index. In such case, please look into the search crawl logs and try to identify the issue and fix it after which you need to run a search full crawl so that the failed content gets updated in the search index.
8.If you have made some changes to the search Crawl rules such as adding, deleting or modifying the crawl rule.
9.When your search index gets corrupted you need to perform a search index reset after which you need to run a full search crawl. Please check my article on search index reset to understand how to perform an index reset and under what circumstances should you be performing a search index reset.
10.The permissions given to the default content access account has been changed.
11. Apart from the above mentioned one’s the system by itself would be performing a search full crawl even when an incremental or continuous crawl is scheduled under the following circumstances:
a)The SharePoint administrator stopped the previous crawl.
b)A content database was restored, or a farm administrator has detached and reattached a content database.
c) A full crawl of the content source has never been done from this Search service application.
d)The crawl database does not contain entries for the addresses that are being crawled. Without entries in the crawl database for the items being crawled, incremental crawls cannot occur.
Thanks for reading this post. Happy SharePointing!!!