I’ve seen the question of how big the page file has to be on a serer several times. As you may know the rule of thumb is to make it 1.5 times the physical RAM.  But sometime system would have a different recommended value for your page file size.

What if you would like to make sure that you are sure about the page file size and you want to prove it with numbers and you calculator?

The best method to determine the correct page file size is to use the following performance counters in perfmon;

   commit limit

   commit charge

(available both in perfmon and task manager )

Commit limit includes memory and page file, so we can easily see how much page file is needed by observing these counters over time.  

Under full application load you need to increase the page file until the commit limit is 20%-30% greater than the commit, (or reduce it if your minimum page file size was higher).  

Since the correct measurements are based on application mix and number of other factors, you can see why the 1.5xRAM rule is just an estimate since we do not have an idea what we are running on the server.

 

We also have an article that shows you a different method on Windows Server 2003 x64;

889654  How to determine the appropriate page file size for 64-bit versions of Windows Server 2003 or Windows XP

http://support.microsoft.com/kb/889654

 

Either method should assist you with calculating the correct page file size on your server.

Until next time.  Cheers!

 

Just found Mark russinovich has a very deep dive about this topic on his Blog;

http://blogs.technet.com/markrussinovich/archive/2008/11/17/3155406.aspx