When you are using multiple server instances, a rebuild process is started on all instances that are currently online and the new version of the data is not activated until the index rebuild process is complete. If the rebuild fails on one or more server instances, the new version will be discarded on all server instances so that all server instances are able to work with the same version. If a server is offline for some time and comes back online, the latest version of all search indexes will be copied from another server to bring it up to date.
The previous rebuild process must have finished. A rebuild process cannot be started while another rebuild process is running. Imported search indexes cannot be rebuilt.
A search index rebuild process can start automatically in the background according to the scheduling rules configured in the search index configuration. If you need to start a rebuild process immediately, you can start the process manually.
To start a rebuild process manually, complete the following steps.