How Rebuilding Content Indexes for Exchange Databases

When the content index for a database has become corrupt, it will need to be rebuilt, or reseeded from another database copy in the DAG. For now, let's look at the process for a non-DAG Mailbox server, and demonstrate the different procedure for DAGs later in this chapter.

This process involves removing the existing content index files, which will trigger Exchange Search to re-index that database. The re-indexing process can cause a high load on the Exchange server, which may impact performance for the server. So you should carefully consider the timing of any content index rebuilds, and how it might impact your end users. The content index files are located in the same path as the database EDB file, in a sub-folder named with a GUID

Before the corrupt index files can be removed, the Exchange Search services must be stopped. While these services are stopped, searches in OWA will not be able to be performed by end users, and all of the database content indexes on the server will be reported as “Failed” by Get-MailboxDatabaseCopyStatus..

PS C:\> Invoke-Command -ComputerName EX2013SRV1 {Stop-Service MSExchangeFastSearch; Stop-Service HostControllerService}

Next, delete the GUID-named folder that contains the content index files. If the folder will not delete due to files in use, then it's likely that either:

• You haven't stopped the correct search services
• Another process, such as file-level anti-virus software, has a lock on the folder (and may be the cause of the index corrupting to begin with)

After deleting the files, start the search services again.

PS C:\> Invoke-Command -ComputerName EX2013SRV1 {Start-Service MSExchangeFastSearch; Start-Service HostControllerService}

After a delay while Exchange Search evaluates the situation, the database will be re-indexed. The content index will have a state of “Crawling” while this is occurring.

[PS] C:\>Get-MailboxDatabaseCopyStatus -Server EX2013SRV1 | ft -auto

Name            Status  CopyQueueLength ReplayQueueLength LastInspectedLogTime ContentIndexState
----            ------  --------------- ----------------- -------------------- -----------------
DB01EX2013SRV1 Mounted 0               0                                      Crawling
DB02EX2013SRV1 Mounted 0               0                                      Healthy
DB03EX2013SRV1 Mounted 0               0                                      Healthy
DB04EX2013SRV1 Mounted 0               0                                      Healthy

You can monitor the progress of the database crawl by watching the MSExchange Search IndexesCrawler: Mailboxes Remaining counter in Performance Monitor for that database instance.