Diagnosing performance issues with SharePoint Online
This article shows you how you can diagnose common issues with your SharePoint Online site using Internet Explorer developer tools.
There are three different ways that you can identify that a page on a SharePoint Online site has a performance problem with the customizations.
The F12 tool bar network monitor
Comparison to a non-customized baseline
SharePoint Online response header metrics
This topic describes how to use each of these methods to diagnose performance issues. Once you've figured out the cause of the problem, you can work toward a solution using the articles about improving SharePoint performance that you can find on http://aka.ms/tune.
Using the F12 tool bar to diagnose performance in SharePoint Online
In this article we use Internet Explorer 11. Versions of the F12 developer tools on other browsers have similar features though they may look slightly different. For information on the F12 developer tools, see:
To bring up the developer tools press F12 and then click the Wi-Fi icon:
On the Network tab, press the green play button to load a page. The tool returns all of the files that the browser requests in order to get the page you asked for. The following screen shot shows one such list.
You can also see the download times of the files on the right side as shown in this screen shot.
This gives you a visual representation of how long the file took to load. The green line represents when the page is ready to be rendered by the browser. This can give you a quick view of the different files that might be causing slow page loads on your site.
Setting up a non-customized baseline for SharePoint Online
The best way to determine your site’s performance weak points is to set up a completely out-of-the-box site collection in SharePoint Online. This way you can compare all the various aspects of your site with what you would get with no customization on the page. The OneDrive for Business home page is a good example of a separate site collection that is unlikely to have any customizations.
Viewing SharePoint response header information
In SharePoint Online and SharePoint Server 2013 you can access the information that is sent back to the browser in the response header for each file. The two most useful values for diagnosing performance issues are SPRequestDuration and X-SharePointHealthScore:
This is the amount of time that the request took on the server to be processed. This can help determine if the request is very heavy and resource intensive. This is the best insight you have into how much work the server is doing to serve the page.
This indicated the health of the server that your SharePoint instance is running on. This number ranges from 0 to 10 where 0 is the most healthy and 10 is the least healthy. This number helps you determine if the server is the bottleneck in your page loading or if it is something specific to your page. The server health score is almost always 0. In SharePoint Online, automated alerts when server health score degrades so you should never expect to see a non-0 score for long.
Ensure that you have the F12 tools installed. For more information on downloading and installing these tools, see What's new in F12 tools.
In the F12 tools, on the Network tab, press the green play button to load a page.
Click one of the .aspx files returned by the tool and then click DETAILS.
Click Response headers.