SQL Defrag Manager allows you to adjust the fill factor and padding for your indexes. The Fill Factor Settings window provides a recent analysis and fragmentation results for the selected index. Use this information to decide whether to adjust your fill factor. The New Values area allows you to enter your new values in the Fill Factor and Pad Index fields. The Current Values area displays your current fill factor and index padding.
Access the Fill Factor Settings window
To display the Fill Factor Settings window, right-click the index for which you want to adjust the fill factor, and then select Adjust Fill Factor SQL Defrag Manager displays this option only when you select an index.
Differences when rebuilding the index online or offline
The Fill Factor Settings window allows you to rebuild the index online or offline based on the optimize performance for your environment. Online rebuilds use more memory because SQL Server builds a new copy of the index in memory while providing access to the index and the underlying table for the duration of the rebuild. Offline rebuilds use less memory because the rebuild occurs on the index itself, which requires that the index is locked and inaccessible for the entire time necessary for the rebuild.
Note that if you perform an offline rebuild on a clustered index, then the entire table is inaccessible until the rebuild completes. This functionality occurs because the leaf-level pages of the clustered index are the physical data pages of the table.