SQL Data Drive Cluster Size = 8192

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Daniel Jameson - 16 Jun 2008 19:29 GMT

Hi,

My impression is that SQL Server always read/writes disk data in 8K pages.
Thus, when I format a hard drive to be used for SQL Server data files, I use
8192 as the cluster size, assuming this will benefit performance. Is this a
justified approach, or are there other considerations I am overlooking?

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Thank you,

Daniel Jameson
SQL Server DBA
Children's Oncology Group
www.childrensoncologygroup.org

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Tom Moreau - 16 Jun 2008 19:39 GMT

Consider 64K cluster size:

http://msdn.microsoft.com/en-us/library/aa178406(SQL.80).aspx

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Tom

----------------------------------------------------
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA, MCITP, MCTS
SQL Server MVP
Toronto, ON Canada
https://mvp.support.microsoft.com/profile/Tom.Moreau

> Hi,
>
> My impression is that SQL Server always read/writes disk data in 8K pages.
> Thus, when I format a hard drive to be used for SQL Server data files, I use
> 8192 as the cluster size, assuming this will benefit performance. Is this a
> justified approach, or are there other considerations I am overlooking?

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Daniel Jameson - 29 Jul 2008 18:00 GMT

Tom,

Thank you. Do you know where I can find this info for SQL 2005 and SQL
2008?

Signature

Thank you,

Daniel Jameson
SQL Server DBA
Children's Oncology Group
www.childrensoncologygroup.org

> Consider 64K cluster size:
>
[quoted text clipped - 10 lines]
> a
>> justified approach, or are there other considerations I am overlooking?

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Tom Moreau - 29 Jul 2008 19:41 GMT

AFAIK, there was no change going to the later releases.

Signature

Tom

----------------------------------------------------
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA, MCITP, MCTS
SQL Server MVP
Toronto, ON Canada
https://mvp.support.microsoft.com/profile/Tom.Moreau

Tom,

Thank you. Do you know where I can find this info for SQL 2005 and SQL
2008?

Signature

Thank you,

Daniel Jameson
SQL Server DBA
Children's Oncology Group
www.childrensoncologygroup.org

> Consider 64K cluster size:
>
[quoted text clipped - 10 lines]
> a
>> justified approach, or are there other considerations I am overlooking?

Reply to this Message

Linchi Shea - 16 Jun 2008 21:05 GMT

> My impression is that SQL Server always read/writes disk data in 8K pages.

That's a wrong impression. SQL Server doesn't always read/write disk data in
8K pages. The SQL Server disk I/O can be as small as 512 byte (e.g. small
transaction log writes), and can be as large as 1MB (e.g. writing to a backup
file).

Linchi

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