Friends, it would be of great deal and help if we had an overall description of ‘what has occurred’ during determining the factors of down SharePoint performance. Below I am listing some of the key point which had clicked to my mind.
• Is issue present on all content databases and sites in a web application?
o If one site is having issues check the URL for the content database the site resides. – This can help determine if the issue is site specific or larger.
o If the content database URL has issues then check other Content databases in the same web application.
o If the web application is having issues validate other web applications in the same method.
o Compare web applications from each SQL server, this can help determine if there is a SQL issue.
• Is the issue present on all WFE's?
o Test from the WFE’s and from a desktop – This can help locate any issues with Network or Load Balancer
o Check WFE events, ULS, IIS, performance monitor
o Do WFE’s have high CPU?
§ Is High CPU on one process/web application
§ Capture all processes organized by CPU utilization
§ Determine what web application is related to process as necessary
• IIS SQL performing well?
o Have the correct Teams such as SA and DBA to validate Wintel Server or SQL for any issues.
• Involvement of all internal teams should be required and record everything for easily sharing and record.
• When involving Microsoft share all event logs, IIS logs, ULS logs, and performance monitor logs captured with them.
A SharePoint performance troubleshooting guide from Idera would also help you to determining the factors to be considered during troubleshooting down SharePoint performance.