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    Hi,<br>
    <br>
    I've a tail -f error.log running, and saw some strange errors,
    repeated each minutes at same second (26), from same host and same
    URL :<br>
    <br>
    <tt>2012/05/22 15:13:26 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.0.26:80/?track=lang-BR&uid=159669961">"http://10.0.0.26:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:14:26 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.1.26:80/?track=lang-BR&uid=159669961">"http://10.0.1.26:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:15:26 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.0.31:80/?track=lang-BR&uid=159669961">"http://10.0.0.31:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:16:26 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.1.31:80/?track=lang-BR&uid=159669961">"http://10.0.1.31:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:17:26 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.0.32:80/?track=lang-BR&uid=159669961">"http://10.0.0.32:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:18:26 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.1.32:80/?track=lang-BR&uid=159669961">"http://10.0.1.32:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:19:26 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.0.33:80/?track=lang-BR&uid=159669961">"http://10.0.0.33:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:20:26 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.1.33:80/?track=lang-BR&uid=159669961">"http://10.0.1.33:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:21:27 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.0.34:80/?track=lang-BR&uid=159669961">"http://10.0.0.34:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:22:27 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.1.34:80/?track=lang-BR&uid=159669961">"http://10.0.1.34:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:23:27 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.0.28:80/?track=lang-BR&uid=159669961">"http://10.0.0.28:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:24:27 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.1.28:80/?track=lang-BR&uid=159669961">"http://10.0.1.28:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:25:27 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.0.25:80/?track=lang-BR&uid=159669961">"http://10.0.0.25:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      2012/05/22 15:26:27 [error] 12410#0: *4714521 upstream timed out
      (110: Connection timed out) while reading response header from
      upstream, client: 177.65.240.189, server: <a class="moz-txt-link-abbreviated" href="http://www.mydomain1.com">www.mydomain1.com</a>,
      request: "GET /?track=lang-BR&uid=159669961 HTTP/1.1",
      upstream: <a class="moz-txt-link-rfc2396E" href="http://10.0.1.25:80/?track=lang-BR&uid=159669961">"http://10.0.1.25:80/?track=lang-BR&uid=159669961"</a>,
      host: "sub.mydomain1.com"<br>
      <br>
    </tt>I've curl this URL, then ab (ApacheBench) it, and wasn't able
    to reproduce this error. Did you have an idea how to debug that ?<br>
    <tt><br>
    </tt>
    <div class="moz-signature">-- <br>
      Greg<br>
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