Whitepaper – Disk Partition Alignment Best Practices for SQL Server

I've blogged some time ago about Microsoft recommendations for maximizing the performances of your disks subsystem for a SQL Server implementation:


SQL Server - Speed up your Disks!



Collection of SQL Server Storage Best Practices



Finally there's available directly from the SQL CAT Team a new whitepaper stating which are the  Microsoft guidelines concerning disk partition alignment.


"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"


You can find it here:



- Beatrice Nicolini -

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