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hvelarde
Asked: 2017-03-17 09:31:46 +0800 CST

How to log the name of backend that responded a request

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I'm using varnishncsa to log requests that are taking to long to be answered on my backend servers using the following command:

varnishncsa -F '%t "%r" %s %T' | awk '$7 > 10 {print}'

I was trying to add information on the backend name but this is not being displayed on varnishncsa output:

sub vcl_backend_response {
    std.log("backend_name:" + beresp.backend.name);
}

what I'm doing wrong?

varnish varnishncsa

1 Answers

  1. Best Answer

    It doesn't work for you because varnishncsa uses "client" mode by default. Enable it using -b switch.

    Subsequently, this will work:

    varnishncsa -b -F '%t "%r" %s %T %{VCL_Log:backend_name}x' | awk '$7 > 10 {print}'

    You might want to check full explanation which includes additional optimization to query slow backend requests.

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