. Net pages occasionally encounter 503 errors under high concurrency, And. net page 503 errors

. Net pages occasionally encounter 503 errors under high concurrency, And. net page 503 errors

We developed a callback page, which is called by a tool. Due to the high pressure, the callback page is load balanced by six servers;

Recently, the Business System has been resized again, and the pressure on the callback page has increased exponentially, resulting in an occasional 503 error during peak hours.

To solve this problem, we first analyze all aspects of the system. On the tool call page, we first go to the F5 server and then to the Page Server;

1. The number of connections to the F5 Server Load balancer server has not reached the warning limit by consulting the corresponding manufacturer;

2. That's why the Page Server is:

1) whether the number of connections has reached the upper limit. In versions earlier than win2008, there is a limit on the number of semi-open connections. However, this limit has been disabled since win7, winvista, and win2008, as shown below:

2) is the request queue in the application pool reached the upper limit?

Baidu: by default, the request queue of each application pool is reserved.1000If the number of requests exceeds the limit, the system returns the 503 error to the client. You can modify the value as needed. The maximum value can be set65535.

This is the problem. After the queue length is set to 10000, the 503 error is solved.

 

. Net website. In the local test, click the delete button on the page to trigger the event normally. When you click the button on the server, Error 404 is displayed.

This problem may occur in many ways.
After you click Delete, is the redirection executed? Is the deletion event executed?

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