HTTP Request Throttling in SharePoint Server 2019

DerekN 

To track down the source of excessive requests causing HTTP request throttling in SharePoint 2019, you can follow these steps:

1. Enable IIS Logging: Start by enabling IIS logging on your SharePoint web front-end servers. This will allow you to capture detailed information about incoming HTTP requests. You can enable logging through the Internet Information Services (IIS) Manager by selecting your website, opening the "Logging" feature, and configuring the log file settings.

2. Analyze IIS logs: Once the logging is enabled, you can analyze the IIS logs to identify patterns and spikes in incoming requests. Look for a surge in requests around the time when the throttling occurs. Pay attention to the source IP addresses, user agents, and URLs of the requests.

3. Use log analysis tools: There are various log analysis tools available that can help you process and analyze the IIS logs effectively. Tools like Microsoft Log Parser, ELK Stack (Elasticsearch, Logstash, and Kibana), or third-party log analysis tools can assist in parsing and visualizing the log data to identify the source of excessive requests.

4. Correlate with system logs: To narrow down the search, correlate the identified patterns in the IIS logs with other system logs such as SharePoint ULS logs, event logs, and any custom logging you have implemented. Look for any related errors or warnings that can help pinpoint the cause of the request spikes.

5. Monitor network traffic: Consider implementing network traffic monitoring tools to capture and analyze network traffic to and from your SharePoint farm. This can help identify any unusual patterns or traffic from specific IP addresses or hosts.

6. Review timer jobs and external processes: Examine the timer jobs running in your SharePoint farm and check if any external processes or scheduled tasks are interacting with your SharePoint environment. Look for any jobs or processes that coincide with the time when the request spikes occur. Especialy check your search service configuration, when its schedule to do incremental and full crawl

By following these steps, you should be able to track down the source of excessive requests causing HTTP request throttling in your SharePoint 2019 farm. It's important to analyze the collected data thoroughly and consider collaborating with your network or system administrators to investigate any potential external factors that may be causing the issue.