IIS 7 and Above
Application Request Routing (ARR)
ARR and 502 errors
Last post Aug 08, 2011 03:39 PM by MaxASPSteve
Mar 21, 2010 03:28 PM|MaxASPSteve|LINK
I am running an IIS 7.5 webfarm using ARR to spread requests. I have enabled ARR caching (both local and secondary), and I have noticed a strange phenomenon occurring frequently. While troubleshooting a problem for a customer, I enabled FRT on the default
website on all ARR servers. I noticed that there were a high number (sometimes as high as 10 per hour) of 502 errors like this:
Mar 21, 2010 04:45 PM|steve schofield|LINK
Just a thought is TCP Chimney Offload disabled?
Windows Server MVP - IIS
Log archival solution
Install, Configure, Forget
Mar 22, 2010 12:18 PM|MaxASPSteve|LINK
RSS is set to enabled, Chimney offload state is automatic.
When I do a netstat-t it shows the offload state of all connections as In Host, so I am not sure if TCP Chimney Offloading is the problem.
Mar 22, 2010 12:30 PM|steve schofield|LINK
are your NICs broadcom by chance? If so I'd suggest disabling the whole SNP settings. It's a worthless setting IMHO.
Mar 22, 2010 02:03 PM|MaxASPSteve|LINK
no they are Intel Pro/1000 MT's.
Apr 23, 2010 05:27 AM|harrisanderson|LINK
I wanna state that i have a problem that is related to the subject if you wanna help me ,then you may
Kindly response me directly through e-mail.Problem is states as under
The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /readTopic.do.
Reason: Error reading from remote server
May 31, 2010 02:56 PM|CedricBoivin|LINK
Oct 28, 2010 04:45 AM|gleysen|LINK
Oct 28, 2010 04:21 PM|MaxASPSteve|LINK
Oct 29, 2010 04:17 AM|gleysen|LINK
Jun 23, 2011 07:17 AM|adigraham|LINK
Did you ever get this fixed please?
Jun 23, 2011 11:27 AM|Rinzler|LINK
I have the same issue, I receive intermittent 502 errors. I have been unable to fix this issue.
Jun 23, 2011 12:20 PM|MaxASPSteve|LINK
In my case a hotfix was released that addressed my issue, something to do with the External Cache (I use multiple ARR servers). What you need to do is distinguish between 502.3 and 502.4...502.4 was the problem I had, I still see 502.3's, however, 99% of
the time they have been related to a problem on the application server.
Aug 08, 2011 12:26 PM|Rinzler|LINK
What hotfix? And how did you set up your Logs to catch just 502.3 and 502.4 ?
Aug 08, 2011 03:39 PM|MaxASPSteve|LINK
As for how to parse your W3C logs, I used logparser (http://www.microsoft.com/download/en/details.aspx?id=24659) and the query below:
It is also fair to point out that my problem was specific to the use of the External Cache feature (when using multiple ARR servers), and the hotfix above addresses that specific issue. I am not sure (although I would imagine it is) if this update is rolled
up in the ARR v 2.5 release or not (so if you are using that version this may be a moot point). Happy hunting anyway!