Web servers are essential elements that are in charge of providing web content online. They perform tasks such as handling requests, managing connections, and maintaining security, making them fundamental components of the internet infrastructure. Well-known web servers include Microsoft Internet Information Services (IIS), Apache HTTP Server, NGINX, and Apache Tomcat. This article will specifically discuss the IIS web server.
Frequent failures, slow webpages, and unexpected delays in response times may indicate potential performance issues with web applications hosted in your IIS web server. By analyzing metrics, traces, and logs together, you can identify problems, optimize performance, and enhance the user experience. Metrics provide performance data for troubleshooting, traces reveal the request and response flow for a better understanding of server behavior, and logs offer comprehensive visibility into your IIS infrastructure to ensure a seamless web application experience for users.
The primary focus of this article will be on the analysis of IIS logs, providing an overview of the key components of metrics and traces for an IIS server.
Understanding IIS logs
IIS is a native web server for hosting websites on Windows platforms while incorporating multiple components to manage requests efficiently.
With Site24x7, you can monitor different types of IIS logs, including:
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IIS access logs: Capture various aspects of web application access, such as user visits, client IP addresses, browser information, response times, and status codes.
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IIS error logs: Capture information about server errors and issues encountered during operation.
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Windows event logs: Provide a detailed overview of system-wide events and activities, including events specific to the IIS server, such as service startup, configuration modifications, application pool recycling, and auditing.
Challenges in log analysis
Managing and monitoring logs for IIS, or any logs in general, can be quite challenging.
Some challenges include:
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Storing a high volume of log data without overwhelming storage resources.
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Sorting and sifting through millions of log lines to facilitate easy retrieval and analysis.
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Aggregating logs from multiple servers and sources into a centralized platform for unified management.
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Deciphering and extracting relevant information from diverse log formats.
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Identifying and correlating related log entries across different sources to gain insights.
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Ensuring scalability to handle increasing data and infrastructure demands.
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Troubleshooting by quickly accessing and analyzing relevant log data to reduce mean time to repair (MTTR).
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Achieving comprehensive observability across distributed environments.
Monitor and manage logs with ease
A centralized platform is crucial for managing log data. Site24x7's centralized, cloud-based log management solution offers comprehensive monitoring and analysis of IIS logs. It correlates logs and metrics on one platform for improved visibility and insights. With observability, admins can track and troubleshoot issues, optimize performance, and maintain a smooth IIS infrastructure.
Explore IIS server metrics, logs, and traces
Site24x7 can help you achieve efficient management of IIS server metrics, logs, and traces.
Metrics
Our IIS server monitoring solution enables you to monitor the availability and performance of your IIS servers actively. It provides real-time insights into server performance, and timely alerts for potential issues.
To monitor your Microsoft IIS server, log in to the Site24x7 portal, go to Server, add an IIS server, and analyze the resource usage of sites, apps, and application pools to avoid server problems.
Here, you can track key server metrics comprehensively, including:
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Network statistics
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Request statistics
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Connection statistics
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User statistics
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Cache memory usage
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Cache hits
There are also log-specific widgets included in the IIS server dashboard that show:
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Response Time Stats
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Status Code Stats
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Top 20 Failed Requests
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Top 10 Slowest Requests
Response Time Stats offer a detailed breakdown and analysis of the time it takes for your web server to respond to incoming requests. This gives you a holistic view of how efficiently your web server handles requests, allowing you to pinpoint areas for improvement. Status Code Stats reveal the distribution of status codes, the Top 20 Failed Requests highlight critical errors, and the Top 10 Slowest Requests pinpoint the transactions causing slowness.
Logs
IIS logs focus on analyzing entries for specific insights. They are used to examine individual requests; errors; and user, server, and application behavior recorded in the logs. This facilitates troubleshooting, identifies patterns, and gathers detailed insights for targeted improvements.
Some common troubleshooting scenarios for IIS access logs include:
- Identifying 500 status code issues through application logs
- Identifying slow requests using application logs
Identifying 500 status code issues through application logs
HTTP status code 500, known as Internal Server Error, signifies that the server encountered an unexpected issue that prevented it from fulfilling the client's request. This generic error lacks specific details about the problem. When a server returns a 500 error, it indicates a server-side problem, possibly caused by misconfigurations, programming errors, or issues with resources. Identifying the root cause requires thorough investigation and troubleshooting.
To investigate the problem further, you can go to the Status Code Stats widget on the IIS server monitoring dashboard (shown in Fig. 2 and displayed in Fig. 3 below) and click the 5XX count that you want to troubleshoot.
You'll notice that the URI Check Availability (Fig. 4) has a high number of failures. Analyzing frequent failures in this specific URI can provide important insights into potential issues affecting its performance.
To delve deeper, click the count of CheckAvailability. This will filter IIS access logs for entries with a status code of either 500 (Internal Server Error) or 599 (Network Connection Timeout Error) and a stem URI of "CheckAvailability."
Troubleshooting real-time application issues often involves comparing logs from different sources. However, this process can be time-consuming and requires opening multiple tabs for each log type and tracing the exact line of an issue. This is where the related log templates feature (Fig. 5) becomes useful, as it allows you to compare multiple fields in one log type with another by creating a template.
In this case, you can utilize the Windows event logs (highlighted in Fig. 5) to view the actual exception trace. By clicking the related log template created for Windows event logs, you can view the specific error details (Fig. 6) associated with the 500 status code.
By following these steps, you can effectively use IIS access logs as a valuable resource to diagnose and resolve HTTP 500 errors.
Identifying slow requests using application logs
Our next use case is to troubleshoot slow requests using application logs. Response Time Stats will give you an understanding of how well your transactions are performing, including any areas that may be experiencing slower processing. By analyzing this data, you can identify which request is taking longer to complete.
To do this, you can go to the Response Time Stats widget on the IIS server monitoring dashboard (shown in Fig. 2 and displayed in Fig. 7 below) and click the highest response time that you want to troubleshoot.
In the resultant window, you can use our powerful query language to organize the data, sorting it by average time taken in descending order.
You can also observe that a specific payment processing request (highlighted in Fig. 8) had a longer processing time. Using our application performance monitoring (APM) solution, you can identify the exact details of the trace responsible for this slow payment processing request.