LeanSentry, the popular ASP.NET and IIS application monitoring tool has been updated with the ability to automatically detect and notify as and when your website is not responding (hangs) in addition to a capability to performs a realtime diagnostic test. The monitoring engine also sends you an alert that tells you exactly what caused the hang including a comprehensive analysis of the problem to enable you to resolve the issue immediately.
LeanSentry continuously monitors each application pool for signs of hangs using standard lightweight monitoring which has virtually zero impact on the production systems. Moreover, monitoring can be done remotely without installing anything on your actual production servers. It automatically take into account the application pool's specific ASP.NET/IIS threading settings that affect request processing including other symptoms which cause hangs.
As soon as LeanSentry monitoring engine suspects a hang, it will snapshot currently executing requests and identify which requests appear queued or blocked. While blocked requests can be easily identified, queued requests can be indentified using a bunch of heuristics. When a hang is confirmed the LeanSentry engine will perform a differential thread snapshot of the process, which will determine where threads are stuck in your application code.
LeanSentry has also added a unique feature to analyze threading and queueing characteristics of the application pool across the HTTP.SYS kernel queue, ASP.NET and IIS. It also generates hung requests e-mails with which you can view the alerts generated during the diagnosis process.
InfoQ got in touch with Michael Volodarsky, Chief Technology Officer, LeanServer to know more about the recent update discussed above.
InfoQ: How does this development benefit developers?
Developers benefit greatly from this feature. Now, whenever a hang happens in production, they can get the information they need to resolve it instantly instead of spending days trying to reproduce the hang in a development environment, or performing very complex production debugging. LeanSentry explains hangs simply so action can be taken right away.
InfoQ: Does the monitor provide steps to prevent hangs?
LeanSentry will provide specific guidance based on what it detects to be causing the hang, including identifying the exact place in the code where the requests are blocked. It also provides guidance on IIS/ASP.NET configuration changes that can be made to reduce the chances of the hang.
InfoQ: Do you have any plan to introduce mobile alerts?
Yes, we plan to add SMS alerts later this year. For now, we are relying on the fact that most IT uses have smartphones and will receive our email notifications for our alerts.