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- retry (default 60secs) - "Connection pool worker retry timeout in seconds. If the connection pool worker to the backend server is in the error state, Apache will not forward any requests to that server until the timeout expires. This enables to shut down the backend server for maintenance, and bring it back online later. A value of 0 means always retry workers in an error state with no timeout."
- ping (not set by default)- "Ping property tells the web server to send a CPING request on ajp13 connection before forwarding a request. The parameter is the delay in seconds to wait for the CPONG reply. This feature has been added to avoid problems with hung and busy Tomcat 's and require ajp13 ping/pong support which has been implemented on Tomcat 3.3.2+, 4.1.28+ and 5.0.13+. 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. Currently this has an effect only for AJP. By adding a postfix of ms the delay can be also set in milliseconds."
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