<div>Dear All,</div><div><br></div><div>we have a strange random backend polling error.</div><div><br></div><div>There is a varnish box (2.1.4 running on debian lenny) for debugging and testing which polls our two production backends:</div>
<div><br></div><div>a) STATICnode - nginx</div><div>b) APACHEnode - apache 2.2.9 with </div><div><br></div><div>Keepalive ON</div><div>Timeout 30</div><div>KeepAliveTimeout 12</div><div>MaxKeepAliveRequests 0</div><div>Prefork-MaxRequestsPerChild 20000</div>
<div><br></div><div>VCL:</div><div><br></div><div><div><div><div>backend APACHEnode {</div><div> .host = "10.0.80.15"; .port = "8082";</div><div> .probe = { .url = "/robots.txt"; .timeout = 10ms; .interval = 1s; .window = 10; .threshold = 9; }</div>
<div>}</div><div>backend STATICnode {</div><div> .host = "10.0.80.11";</div><div> .port = "8080";</div><div> .probe = { .url = "/robots.txt"; .timeout = 300ms; .interval = 2s; .window = 10; .threshold = 8; }</div>
<div>}</div></div></div></div><div><br></div><div><br></div><div>The test case is for simulating our production varnish server, which acts exactly the same way...</div><div><br></div><div>Here is the varnishlog:</div><div>
<br></div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.000914 0.000993 HTTP/1.1 200 OK</div><div> 0 Backend_health - STATICnode Still healthy 4--X-RH 10 8 10</div><div>0.000354 0.000371 HTTP/1.1 200 OK</div>
<div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.000686 0.000917 HTTP/1.1 200 OK</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.000639 0.000847 HTTP/1.1 200 OK</div>
<div> 0 Backend_health - STATICnode Still healthy 4--X-RH 10 8 10</div><div>0.000400 0.000379 HTTP/1.1 200 OK</div><div> 0 CLI - Rd ping</div><div> 0 CLI - Wr 200 19 PONG 1304944200 1.0</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div>
<div>0.000685 0.000807 HTTP/1.1 200 OK</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.000696 0.000779 HTTP/1.1 200 OK</div><div> 0 Backend_health - STATICnode Still healthy 4--X-RH 10 8 10</div>
<div>0.000366 0.000376 HTTP/1.1 200 OK</div><div><span class="Apple-style-span" style="background-color: rgb(255, 0, 0); "> 0 Backend_health - APACHEnode Went sick 4--X--- 8 9 10 0.000000</span></div><div><span class="Apple-style-span" style="background-color: rgb(255, 0, 0);">0.000779 HTTP/1.1 200 OK</span></div>
<div><span class="Apple-style-span" style="background-color: rgb(255, 0, 0);">Date: Mon, 09 May 2011 12:30:02 GMT</span></div><div><span class="Apple-style-span" style="background-color: rgb(255, 0, 0);">Server: Apache/2.2.9</span></div>
<div><span class="Apple-style-span" style="background-color: rgb(255, 0, 0);">Last-Modified: Fri, 08 Apr 2011 09:52:29 GMT</span></div><div><span class="Apple-style-span" style="background-color: rgb(255, 0, 0);">ETag:</span></div>
<div> 0 CLI - Rd ping</div><div> 0 CLI - Wr 200 19 PONG 1304944203 1.0</div><div> 0 Backend_health - APACHEnode Still sick 4--X-RH 8 9 10 0.002321</div><div>0.001165 HTTP/1.1 200 OK</div><div> 0 Backend_health - STATICnode Still healthy 4--X-RH 10 8 10</div>
<div>0.000367 0.000373 HTTP/1.1 200 OK</div><div> 0 Backend_health - APACHEnode Back healthy 4--X-RH 9 9 10 0.001611</div><div>0.001276 HTTP/1.1 200 OK</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div>
<div>0.000676 0.001126 HTTP/1.1 200 OK</div><div> 0 Backend_health - STATICnode Still healthy 4--X-RH 10 8 10</div><div>0.000391 0.000378 HTTP/1.1 200 OK</div><div> 0 CLI - Rd ping</div><div> 0 CLI - Wr 200 19 PONG 1304944206 1.0</div>
<div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.006641 0.002505 HTTP/1.1 200 OK</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.002885 0.002600 HTTP/1.1 200 OK</div>
<div> 0 Backend_health - STATICnode Still healthy 4--X-RH 10 8 10</div><div>0.000436 0.000392 HTTP/1.1 200 OK</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.000750 0.002137 HTTP/1.1 200 OK</div>
<div> 0 CLI - Rd ping</div><div> 0 CLI - Wr 200 19 PONG 1304944209 1.0</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.000787 0.001800 HTTP/1.1 200 OK</div><div> 0 Backend_health - STATICnode Still healthy 4--X-RH 10 8 10</div>
<div>0.000384 0.000390 HTTP/1.1 200 OK</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div><div>0.000720 0.001530 HTTP/1.1 200 OK</div><div> 0 Backend_health - APACHEnode Still healthy 4--X-RH 9 9 10</div>
<div>0.000825 0.001354 HTTP/1.1 200 OK</div><div>^C</div><div><br></div><div># varnishstat -1</div><div><br></div><div>client_conn 0 0.00 Client connections accepted</div><div>client_drop 0 0.00 Connection dropped, no sess/wrk</div>
<div>client_req 0 0.00 Client requests received</div><div>cache_hit 0 0.00 Cache hits</div><div>cache_hitpass 0 0.00 Cache hits for pass</div><div>cache_miss 0 0.00 Cache misses</div>
<div>backend_conn 0 0.00 Backend conn. success</div><div>backend_unhealthy 0 0.00 Backend conn. not attempted</div><div>backend_busy 0 0.00 Backend conn. too many</div>
<div>backend_fail 0 0.00 Backend conn. failures</div><div>backend_reuse 0 0.00 Backend conn. reuses</div><div>backend_toolate 0 0.00 Backend conn. was closed</div>
<div>backend_recycle 0 0.00 Backend conn. recycles</div><div>backend_unused 0 0.00 Backend conn. unused</div><div><br></div><div><br></div><div>Can anyone give us a hint for tracking down this error?</div>
<div>Much Obliged</div><div><br></div><div>Jonas</div>