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Article ID: 926930 - Last Review: May 14, 2013 - Revision: 4.0

INTRODUCTION

Microsoft SQL Server currently supports the following sector sizes that are equal to or less than 4 kilobytes (KB):

  • Physical sector sizes that evenly divide into 4 KB
  • Physical sector sizes that are smaller than the size of the original formatted sector size of the database, as long as the smaller sector size is evenly divisible into the originally formatted sector size
  • 512 bytes
  • 1,024 bytes
  • 2,048 bytes
  • 4,096 bytes

Note Microsoft SQL Server supports disk drives that have standard native sector sizes of 512 bytes and 4 KB.

More information

SQL Server requires correct reporting of physical sector size to maintain data safety and avoid data loss. Avoidance of sector rewrites is a fundamental requirement of SQL Server. We do not support the read, write, and modify behavior that logical sector size reporting causes.

For more information about support for larger sector sizes, see the "4-KB disk sector sizes" section in the following white paper:
http://technet.microsoft.com/en-us/library/cc917726.aspx (http://technet.microsoft.com/en-us/library/cc917726.aspx)
If you are using Advanced Format Disks that are physically formatted with 4,096 bytes, but expose a logical sector size of 512 bytes, then you must update your SQL Server systems with the following fixes to be in a supported state:
  • Windows Update to enable correct recognition and reporting of physical and logical sector size:
    • 2553708  (http://support.microsoft.com/kb/2553708/en-us/ ) A hotfix rollup that improves Windows Vista and Windows Server 2008 compatibility with Advanced Format disks
    • 982018  (http://support.microsoft.com/kb/982018/en-us/ ) An update that improves the compatibility of Windows 7 and Windows Server 2008 R2 with Advanced Format Disks is available
  • SQL Updates to use the updated logical and physical sector sizes in the SQL Server transaction log manager:
    • SQL Server 2008 R2 Service Pack 1 and later versions of SQL Server 2008 R2
    • SQL Server 2012 RTM and later versions of SQL Server 2012
The disk drive manufacturer specification should indicate whether the drive is an Advanced Format Disk. After you apply the Windows updates, utilities such as fsutil start reporting both the physical and logical sector sizes. If you use Advanced Format Disks without the updates that are mentioned earlier in this section, there is a risk of potential data loss and performance issues. This is because the drive firmware has to perform Read-Modify-Write to support the logical 512-byte and physical 4,096-byte sector mappings. For more information about this behavior, visit the following MSDN website:
http://blogs.msdn.com/b/psssql/archive/2011/01/13/sql-server-new-drives-use-4k-sector-size.aspx (http://blogs.msdn.com/b/psssql/archive/2011/01/13/sql-server-new-drives-use-4k-sector-size.aspx)
Note Disk drives that have native 4KB sector size (both physical and logical) will work fine without the Windows and SQL updates that are mentioned earlier in this section.

Additional Information

Collapse this tableExpand this table
Rule softwareRule titleRule descriptionProduct versions against which the rule is evaluated
System Center AdvisorSQL Server Database might reside in an Advanced format type (512E)System Center Advisor detected the presence of one or more databases residing in the  Advanced Format or 512E (4K physical and 512-byte logical sector size) drives. SQL Server 2008 is not supported on such emulators, for SQL Server 2008 R2 we recommend to be at SP1 to host databases on 512E drives. Review the information in this article and take corrective actions appropriatelySQL Server 2008 R2

SQL Server 2012




Applies to
  • Microsoft SQL Server 2005 Developer Edition
  • Microsoft SQL Server 2005 Enterprise Edition
  • Microsoft SQL Server 2005 Enterprise Edition for Itanium-based Systems
  • Microsoft SQL Server 2005 Enterprise X64 Edition
  • Microsoft SQL Server 2005 Standard Edition
  • Microsoft SQL Server 2005 Standard X64 Edition
  • Microsoft SQL Server 2005 Standard Edition for Itanium-based Systems
  • Microsoft SQL Server 2005 Workgroup Edition
  • Microsoft SQL Server 2008 Developer
  • Microsoft SQL Server 2008 Enterprise
  • Microsoft SQL Server 2008 Standard
  • Microsoft SQL Server 2008 Workgroup
  • Microsoft SQL Server 2008 R2 Datacenter
  • Microsoft SQL Server 2008 R2 Developer
  • Microsoft SQL Server 2008 R2 Enterprise
  • Microsoft SQL Server 2008 R2 Standard
  • Microsoft SQL Server 2008 R2 Workgroup
  • Microsoft SQL Server 2012 Developer
  • Microsoft SQL Server 2012 Enterprise
  • Microsoft SQL Server 2012 Standard
Keywords: 
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