Applies to: Windows Server 2003/R2, Windows Server 2008, Windows Server 2008 R2 and Windows Server 2012

Context:

In forums every now and then people ask questions about setting up page files on Windows Servers, Minimum disk size for OS partition and their best practices. Hence I thought of writing my views in this Wiki article !

If you are  reading this article I presume that, you might know What is Pagefile in Windows and why that is needed etc..., I am not going to write the stuff which can be searched and found easily. 

Description:

*** Here are the best practices which I follow, they are NOT Microsoft Recommendations !!! ***

As a best practice, you need to set page file "1.5 times" the RAM or memory available on any Windows Servers.

Servers hosting Databases or resource hungry applications like SAP are recommended to have page file set "3 times" the the RAM or memory available.

Also, it is recommended to split page file on two different drives (Preferably on two different Physical/Virtual Disks) on the server for better disk I/O performance. 

For Windows Server 2003, OS (C drive) partition size should be set as 40 GB irrespective of OS version (Std, Ent etc…) and platform (32bit or 64bit) and C drive should have 4 GB page file.

For Windows 2008, Windows Server 2008R2 and Windows Server 2012,  OS (C drive) partition size should be set as 66 GB irrespective of OS version (Std, Ent etc…)  and platform (32bit or 64bit) and C drive should have 6 GB page file.

Is it OK to split page file ? Is that an recommended approach ?

Answer is Yes !

Now a days, usually servers have more than 16 GB RAM in an Enterprise level setup.Here is an example with which I would try to explain how you can split the page file.

Say, you have 16 GB RAM on a server, 1.5 times the RAM 16 GB = 24 GB;  you need to set 24 GB Page file on the Server.

Now, how would you distribute the page file ? Here is the way,

You need to create a separate Drive (Let's say drive P)  and split the Page file (other than the preset page file on C drive).

For Windows Server 2003, C drive already has 4 GB, now on a newly created drive P,  set 20 GB page file (i.e. 24 - 4=20 GB), make sure you have at least 25 GB "P" Drive to accommodate 20 GB page file.

For Windows 2008, Windows Server 2008R2 and Windows Server 2012, C drive already has 6 GB, now on a newly created drive P, set 18 GB page file (i.e. 24 - 6=18 GB), make sure you have at least 23 - 25 GB "P" Drive to accommodate 18 GB page file.

What is the recommended size for page file  if server has 128 GB or 256 GB or 512 GB or 1 TB RAM ?

Theoretical answer is, page file should be 1.5 times the RAM available on server however, practically it's not always feasible  to set huge amount of page file on server as it requires very large disk space. For the server's with heavy amount of RAM, you might want to limit the Page File size equal to 128 GB at least.

P.S. You may choose OS partition size as more than 66 GB as well such has 70 GB or 80 GB. However, pagefile calculations remains the same.

Hope that helps.

- End of the article -

See Also:

What is the Page File for anyway?

Learn Best Practices for Optimizing the Virtual Memory Configuration

Adjusting Paging File Size - Old article however, contents are still relevant !

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