Disk partition alignment is a best practice. Now that SQL Server wait stats are formally documented & DMVs are available, disk partition alignment may be the best-kept secret related to SQL Server performance optimization.
In combination with stripe unit size & file allocation unit size, you can increase I/O throughput by 10%, 30%, or more. In the lab & in the field we commonly see performance enhancements of 30% - 40% by a variety of metrics.
Though Windows Server 2008 provides for out-of-the-box alignment for new partitions, disk partition alignment remains a relevant technology. Disk partition alignment will remain relevant until Windows Server 2003 is retired & existing partitions are re-built. Read more...
Jimmy May, MCDBA, MCSE, MCITP: DBA + DB DevSenior Performance Consultant: SQL ServerACE: Assessment Consulting & Engineering Serviceshttp://blogs.msdn.com/jimmymayPerformance is paramount: Asking users to wait is like asking them to leave.
My Related Posts:
Disk Partition Alignment (Sector Alignment) for SQL Server: Part 2: Adding HP EVA 8000 to Veritas Enterprise Administrator “Track Alignment Settings” Dialog
Jimmy May is sharing a very good slide-deck about the importance of Disk Partition Alignment. http://blogs.msdn.com/ace_team/archive/2008/11/04/disk-partition-alignment-sector-alignment-part-i-slide-deck.aspx