After a recent Exchange 2010 crash at a client, We ran into an issue with a “Crawling” Content Index State. Everything was up and running as expected, all the databases were mounted and the copies were healthy, but the ContentIndexState on several of the databases was in a failed or crawling state.
The first thing we tried was updating the copy: Update-MailboxDatabaseCopy -Identity DB1MBX1 –CatalogOnly
This worked for the failed databases, but those that were stuck in the Crawling state would not update. So I went down the troubleshooting steps in Diagnose Exchange Search Issues and even Reseeded the copy (Reseed the Search Catalog) to no avail. I then tried suspending the DAG copy, removing the catalog directories of both the Primary and Copy, and allowing the entire catalog to be rebuilt. Finally, I removed the DAG copy entirely and tried rebuilding the copy. The end result was always the same: Crawling. ????
So I started digging a little deeper into the health of the Exchange Server and the DAG itself. I finally discovered that the DAG Cluster Name was offline, which prevented the activation of the copy database and the seeding of the Content Index. In our case, starting the DAG Cluster Name in the Cluster services MMC allowed the seeding to occur and the ContentIndexState to reach a healthy state.