SharePoint Pain

Symptoms The load balancer (F5) stopped sending web traffic to one of its pool members (SharePoint frontend) because it detected that the server was down.  Diagnosis IIS logs show the load balancer probes as follows: Note that the HTTP status code ( sc-* ) is recorded as  0.0.2 . The Win32 status  of  2  -- which commonly corresponds to ERROR_FILE_NOT_FOUND   when a default page (such as default.aspx or index.html) is missing -- is misleading in a SharePoint context. SharePoint does not store a default page in the site's root directory, and the load balancer is not configured to query default files.  What's more relevant here is that the server returned  0 bytes to the client and logged a 0 ms response time , indicating the request failed immediately in IIS before reaching the SharePoint/application layer. Therefore, the failure likely occurred earlier in the request pipeline during the native module handoff. While multiple factors could cause s...