HI Sudheer, Thanks for the reply. I couldn’t think of any reason either, but I wanted to check with the community.
Just for clarification. We’re not using the Collapsed-Forwarding plugin explicitly, I understood that that plugin was deprecated in favor of the three configuration areas I mentioned: * Read While Writer * Open Read Retry Timeout * Open Write Fail Action We certainly don’t have the Collapsed-Forwarding plugin in the plugin.config and we are seeing request coalescing. Thanks, Nick From: Sudheer Vinukonda <[email protected]<mailto:[email protected]>> Reply-To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Date: Thursday, March 8, 2018 at 11:49 AM To: "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>> Subject: Re: Parent.config and thundering herd. I haven’t looked at parent proxy setup much, but at a high level, I can’t think of any reason why an origin failover mechanism would impact request coalescing using collapsed forwarding plugin. The open write fail action works based on the cache key for the object and as long as that doesn’t change, it shouldn’t matter which origin it is pulled from. As a matter of fact, we have had origin failover setup using a custom plugin as well as request coalescing enabled in our HLS delivery servers and didn’t see any problems with it. Is it possible the access failures are resulting in preventing the object from being downloaded or being cached somehow? If the object is never cached, then you will see problems with request coalescing. Thanks, Sudheer On Mar 8, 2018, at 7:25 AM, Dunkin, Nick <[email protected]<mailto:[email protected]>> wrote: Hi, We’ve been using the Thundering Herd protection provided by Read While Writer, Open Read Retry Timeout and Open Write Fail Action and have been getting some great results. However the behavior seems to change when we start using parent.config in order to provide some simple origin failover (I.e simple Primary/Secondary Origin kind of thing). My initial tests are showing multiple access failures and not very much in the way of request coalescing. I don’t all have the details with me now, but at a high level, should we expect Read While Writer, Open Read Retry Timeout and Open Write Fail Action to all work in the same way when proxy.config.http.parent_proxy_routing_enable is enabled and we have a simple Primary/Secondary Origin configured with "parent_is_proxy=false”? Especially when most of the time the Primary Origin will be up and available. Are there any gotchas we should be aware of? All this testing is with ATS 7.0 currently. Thanks for your insight. Nick Nick Dunkin Principal Engineer o: 678.258.4071 e: [email protected]<mailto:[email protected]> 4375 River Green Pkwy # 100, Duluth, GA 30096, USA <319E5E02-1647-4542-836C-D389403ADE5F.png>
