SharePoint Search – Full vs Incremental Crawl

I hope following information might help while working on SharePoint Full and Incremental Crawls scheduling, this information provided considering SharePoint content only.

Basic information about Content Sources:

1. Create individual Content Source for each Web Application

Note:

1. On removal of particular URL from exiting content source will trigger Delete operation to remove indexed items from that particular Content Source.
2. On new Content Source creation, though you have not selected option to trigger Full Crawl, on successful save SharePoint triggers Full Crawl.
3. Stopping in progress Incremental Crawl will force Full Crawl on next Incremental Crawl.

Full Crawl Considerations or Required :

1. When SharePoint Farm updated or applied with any new Service Packs/Cumulative Updates/Hot Fixes.
2. When Crawl rules changed – Adding/Modifying/Deleting involves external site URLs.
3. When Incremental Crawl failed for any reasons or stopped.
4. When a new Manage Metadata property used for refinements or filtering.
5. To detect Security changes done on file share since last crawl.
6. Creating/Adding a new Server name mapping.
7. When a new Content Source has been created.

Incremental Crawl Considerations  or Required :

1. Adding a new document or a List Item.
2. Editing/Deleting a document or list item.
3. Change in Security (ex: Adding/Editing/Deleting groups, Adding or Removing users from groups and Changing library permissions

Delete :

1. This will be triggered when URLs from a exiting Content Source are removed.

Hope this information helps!