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From William A Rowe Jr <>
Subject mod_proxy ping docs
Date Wed, 15 Feb 2017 16:28:14 GMT

BalancerMember parameter "ping":

"Ping property tells the webserver to "test" the connection to the
backend before forwarding the request. For AJP, it causes
mod_proxy_ajp to send a CPING request on the ajp13 connection
(implemented on Tomcat 3.3.2+, 4.1.28+ and 5.0.13+). For HTTP, it
causes mod_proxy_http to send a 100-Continue to the backend (only
valid for HTTP/1.1 - for non HTTP/1.1 backends, this property has no
effect). In both cases, the parameter is the delay in seconds to wait
for the reply. This feature has been added to avoid problems with hung
and busy backends. This will increase the network traffic during the
normal operation which could be an issue, but it will lower the
traffic in case some of the cluster nodes are down or busy. By adding
a postfix of ms, the delay can be also set in milliseconds."

Do we mean 100-Continue? Or was this actually an "OPTIONS * HTTP/1.1"
or similar health-check request? 100-Continue isn't really a ping-ack
query, it would only be applicable once a request is sent, and ping
implies that the health is checked *before* sending the request.

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