SQL Server Techical Article
Published: May 2009
Authors: Jimmy May (MS IT Assessment, Consulting, & Engineering (ACE) | bio), Denny Lee
Contributors: Mike Ruthruff, Robert Smith, Bruce Worthington, Jeff Goldner, Mark Licata, Deborah Jones, Michael Thomassy, Michael Epprecht, Frank McBath, Joseph Sack, Matt Landers, Jason McKittrick, Linchi Shea, Juergen Thomas, Emily Wilson, John Otto, Brent Dowling
Technical Reviewers: Mike Ruthruff, Robert Smith, Bruce Worthington, Emily Wilson, Lindsey Allen, Stuart Ozer, Thomas Kejser, Kun Cheng, Nicholas Dritsas, Paul Mestemaker, Alexei Khalyako, Mike Anderson, Bong Kang
Disk partition alignment is a powerful tool for improving SQL Server performance. Configuring optimal disk performance is often viewed as much art as science. A best practice that is essential yet often overlooked is disk partition alignment. Windows Server 2008 attempts to align new partitions out-of-the-box, yet disk partition alignment remains a relevant technology for partitions created on prior versions of Windows.
This paper documents performance for aligned and nonaligned storage and why nonaligned partitions can negatively impact I/O performance; it explains disk partition alignment for storage configured on Windows Server 2003, including analysis, diagnosis, and remediation; and it describes how Windows Server 2008 attempts to remedy challenges related to partition alignment for new partitions yet does not correct the configuration of preexisting partitions.
The following topics are also included: background information, implementation, vendor considerations, two essential correlations, valid starting partition offsets, and the simple protocol to align partitions, define file allocation unit size, and assign drive letters. It includes results from tests that show how partition alignment can affect performance for SQL Server 2008.
For more information, please refer to the Disk Partition Alignment Best Practices for SQL Server whitepaper.
You can also download a Microsoft Word version of this article.
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