We recommend that you perform weekly index rebuilds on the Migration Manager for Email Archives Directory Database and each Item Database. This is particularly important when ‘Item Gathering’ is being performed where a large amount of data is being added to the Item Databases.
Migration Manager for Email Archives contains a new ‘Index Fragmentation’ page in the Admin Interface. This page shows the current levels of Index Fragmentation in the Migration Manager for Email Archives databases. This page also color-codes the rows to help highlight any potential problems, as follows:
Yellow – Page count > 1000, average fragmentation 10-30%
Red – Page count > 1000, average fragmentation >30%
TIP: Perform online Index Rebuilds in SQL Server weekly.
Details for configuring Index rebuilds for specific versions of SQL Server is outside the scope of this document. It is important to note that there are editions of SQL Server where the Index rebuild operation can be performed with the index online, and there are editions of SQL Server where the Index rebuild will cause the index to be made offline while the operation is performed. According to Microsoft documentation (referenced below), online index operations can be performed in SQL Server Developer Evaluation and Enterprise Editions.
If the edition of SQL Server in use for the migration does not support online index rebuilds, make sure to schedule the rebuild operations when there is a low level of activity from Migration Manager for Email Archives .
NOTE: In many environments performance has been seen to dramatically increase if index rebuild and statistics updates are performed daily. Check the index fragmentation page frequently to see if this will help in a specific environment.