Synchronizing And Coordinating Processes On A Web Farm?
Oct 15, 2010
in my ASP.NET app happen asynchronously (i.e in background threads without any access to HttpContext). Let me take an example of one such action. The app would be deployed to a web farm soon.
The background threads would be processing files deposited to a network share location. So, when the app starts, I create a FilesystemWatcher to monitor activities on the desired network share folder.
As soon as a new file arrives, the code processes it and marks it as completed processing.
The problem is with multiple servers watching the same network share, the same file might get processed on different machines, meaning redundant results. On a single server, I use locking mechanisms to prevent race conditions.
Now how to prevent the same on a web farm?
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We have an array of about 12 servers serving a website. Over the past few hours, one single server has started throwing exceptions for WebResource.axd and ScriptResource.axd requests.
Exception
System.Web.HttpException - This is an invalid script resource request.
Stack Trace
at System.Web.Handlers.ScriptResourceHandler.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
Broken server URL
/WebResource.axd?d=S6kjkBsrIKni9uO5HCkv0c8eYObzibWXn9R6A7Yr_Fy7CW4dRFZm1HfcnUTEZ8xBYZDM-5zeTVk1tTgC1hp7d5YYw3o1&t=634308186300177825
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/WebResource.axd?d=yj6PW1hbOvqhMkOh2gYGlw2&t=634207187366247462
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