Subscribe to Windows IT Pro

 

Get Newsletters

  • Get the Latest News
  • Product Updates
  • Helpful Tricks
  • Productivity Tips

Subscribe Now!

September 29, 1999 12:00 AM

Why do I see page faults/sec above 0 when I have a dedicated SQL Server machine?

Windows IT Pro
InstantDoc ID #14143
Rating: (0)

A. This is because "page faults" are NOT the same as paging to disk. A page fault occurs every time SQL accesses a page in memory that is outside it's "working set". Due to the way that the SQL performance monitor counters work in SQL 6.5 and earlier, this area of memory is held outside of the SQL working set, so access/updates to these counters actually CAUSE page faults. 

However most page faults are still to areas that are still held in memory and so do not result in expensive/slow reads/writes to the pagefile on disk. There is some CPU overhead caused by the NT Virtual Memory Manager (VMM) becoming involved and context switches, but these don't affect performance unless you are getting hundreds/thousands of page faults/sec.

The counter you should monitor is pages/sec which is the actual i/o caused to the pagefile, and is what you should be worried about.

For more information on performance/monitoring issues there is no better reference than the NT Server Resource Kit that has a volume dedicated to these topics.


Related Content:

ARTICLE TOOLS

Comments
    There are no comments to display. Be the first one!
You must log on before posting a comment.

Are you a new visitor? Register Here

advertisement

advertisement

White Papers

Get your Windows 7 deployment off to the right start by implementing PC lockdown. A locked-down environment is easier and cheaper to support since users are less likely to make unnecessary changes to the core system configuration - read more here!

Essential Guides

Is your iSCSI "lossy"? The reality is that most off-the-shelf Ethernet hardware deployed for iSCSI can lose packets, resulting in slow performance or application downtime. Learn how to assess your current iSCSI infrastructure and engineer an advanced iSCSI SAN infrastructure.

Web Seminars

What's the best way to keep your network safe from malware? In this web seminar, security expert Greg Shields suggests an alternative method to the traditional blacklisting approach that is common with anti-virus and anti-malware solutions.

eLearning Series

We bring the experts direct to you to share their real-world perspective and expertise. During each event, three sessions stream in real time, so you can learn, ask questions, and get solutions.
Upcoming event: Getting the Most with Exchange 2010 with Paul Robichaux

Subscribe to Windows IT Pro!

Windows is a trademark of the Microsoft group of companies. Windows IT Pro is used by Penton Media Inc. under license from owner.