Apache JK Tomcat Cluster problem

These days by the cluster concurrency problem quickly toss dead, look at which high man look at exactly where the problem arises.
Apache server is normal, each server tomcat is normal, but when the number of Apache connections reached about 300, JK will appear the following exception information, and then the entire system crashed, these are accessed through JK, can not be opened. However, the access to each sub-server is normal. If you restart Apache, the access speed is very smooth. So now the preliminary decision is JK's problem.

The JK work.properties is configured as follows:

Set the TOMCAT1 for the Server

Worker.list=loadbalancer,status,tomcat1,tomcat6,tomcat7
worker.tomcat1.port=8009
Worker.tomcat1.host=localhost
Worker.tomcat1.type=ajp13
worker.tomcat1.lbfactor=2

Set the TOMCAT2worker.tomcat2.port=8009worker.tomcat2.host=192.168.1.203Worker.tomcat2.type=ajp13Worker.tomcat2.lbfactor=1Worker.loadbalancer.type=lbWorker.loadbalancer.balance_workers=tomcat2Set the TOMCAT5 for the Front

worker.tomcat5.port=9009
Worker.tomcat5.host=localhost
Worker.tomcat5.type=ajp13
Worker.tomcat5.lbfactor=1

Set the TOMCAT6 for the Cluster

worker.tomcat6.port=8009
worker.tomcat6.host=110.121.211.205
Worker.tomcat6.type=ajp13
Worker.tomcat6.lbfactor=1

Set the TOMCAT7 for the Cluster

worker.tomcat7.port=7009
worker.tomcat7.host=110.144.0.154
Worker.tomcat7.type=ajp13
Worker.tomcat7.lbfactor=1

Worker.loadbalancer.type=lb
Worker.lb_s.retries=3
Worker.recovery_options=3
Worker.loadbalancer.balance_workers=tomcat1,tomcat7,tomcat6

Worker.status.type=status

[Thu APR 30 14:43:29 2015] [26545:14544] [INFO] service::jk_lb_worker.c (1098): Service failed, worker TOMCAT1 is in error state
[Thu APR 30 14:43:29 2015] [26586:14544] [ERROR] AJP_CONNECTION_TCP_GET_MESSAGE::JK_AJP_COMMON.C (951): (Tomcattaohandan) can ' t receive the Response message from Tomcat, network problems or Tomcat (10.144.211.205:8009) was down (errno=104)
[Thu APR 30 14:43:29 2015] [26586:14544] [ERROR] AJP_GET_REPLY::JK_AJP_COMMON.C (1592): (Tomcattaohandan) Tomcat is down or refused connection. No response have been sent to the client (yet)
[Thu APR 30 14:43:29 2015] [26586:14544] [info] ajp_service::jk_ajp_common.c (1902): (Tomcattaohandan) receiving from Tomcat failed, recoverable Operation Attempt=0
[Thu APR 30 14:43:29 2015] [26586:14544] [info] ajp_service::jk_ajp_common.c (1941): (Tomcattaohandan) Sending request to Tomcat failed, Recoverable Operation Attempt=1
[Thu APR 30 14:43:30 2015] [26769:14544] [ERROR] AJP_CONNECTION_TCP_GET_MESSAGE::JK_AJP_COMMON.C (951): (Tomcattaohandan) can ' t receive the Response message from Tomcat, network problems or Tomcat (10.144.211.205:8009) was down (errno=104)
[Thu APR 30 14:43:30 2015] [26769:14544] [ERROR] AJP_GET_REPLY::JK_AJP_COMMON.C (1592): (Tomcattaohandan) Tomcat is down or refused connection. No response have been sent to the client (yet)
[Thu APR 30 14:43:30 2015] [26769:14544] [info] ajp_service::jk_ajp_common.c (1902): (Tomcattaohandan) receiving from Tomcat failed, recoverable Operation Attempt=1
[Thu APR 30 14:43:30 2015] [26769:14544] [info] ajp_service::jk_ajp_common.c (1941): (Tomcattaohandan) Sending request to Tomcat failed, Recoverable Operation attempt=2
[Thu APR 30 14:43:30 2015] [26769:14544] [ERROR] AJP_SERVICE::JK_AJP_COMMON.C (1953): (Tomcattaohandan) connecting to Tomcat failed. Tomcat is probably not started or was listening on the wrong port
[Thu APR 30 14:43:30 2015] [26769:14544] [INFO] service::jk_lb_worker.c (1098): Service failed, worker Tomcattaohandan is in error state
[Thu APR 30 14:43:31 2015] [26620:14544] [ERROR] AJP_CONNECTION_TCP_GET_MESSAGE::JK_AJP_COMMON.C (951): (TOMCAT1) can ' t receive the response Message from Tomcat, network problems or Tomcat (127.0.0.1:8009) was down (errno=104)
[Thu APR 30 14:43:31 2015] [26620:14544] [ERROR] AJP_GET_REPLY::JK_AJP_COMMON.C (1592): (TOMCAT1) Tomcat is down or refused connection. No response have been sent to the client (yet)
[Thu APR 30 14:43:31 2015] [26620:14544] [info] ajp_service::jk_ajp_common.c (1902): (TOMCAT1) receiving from Tomcat failed, recoverable operation a Ttempt=0
[Thu APR 30 14:43:31 2015] [26620:14544] [info] ajp_service::jk_ajp_common.c (1941): (TOMCAT1) Sending request to Tomcat failed, recoverable Operati On Attempt=1
[Thu APR 30 14:43:31 2015] [26618:14544] [ERROR] AJP_CONNECTION_TCP_GET_MESSAGE::JK_AJP_COMMON.C (951): (Tomcattaohandan) can ' t receive the Response message from Tomcat, network problems or Tomcat (10.144.211.205:8009) was down (errno=104)
[Thu APR 30 14:43:31 2015] [26618:14544] [ERROR] AJP_GET_REPLY::JK_AJP_COMMON.C (1592): (Tomcattaohandan) Tomcat is down or refused connection. No response have been sent to the client (yet)
[Thu APR 30 14:43:31 2015] [26618:14544] [info] ajp_service::jk_ajp_common.c (1902): (Tomcattaohandan) receiving from Tomcat failed, recoverable Operation Attempt=0
[Thu APR 30 14:43:31 2015] [26618:14544] [info] ajp_service::jk_ajp_common.c (1941): (Tomcattaohandan) Sending request to Tomcat failed, Recoverable Operation Attempt=1
[Thu APR 30 14:43:32 2015] [26770:14544] [ERROR] AJP_CONNECTION_TCP_GET_MESSAGE::JK_AJP_COMMON.C (951): (Tomcattaohandan) can ' t receive the Response message from Tomcat, network problems or Tomcat (10.144.211.205:8009) was down (errno=104)
[Thu APR 30 14:43:32 2015] [26770:14544] [ERROR] AJP_GET_REPLY::JK_AJP_COMMON.C (1592): (Tomcattaohandan) Tomcat is down or refused connection. No response have been sent to the client (yet)
[Thu APR 30 14:43:32 2015] [26770:14544] [info] ajp_service::jk_ajp_common.c (1902): (Tomcattaohandan) receiving from Tomcat failed, recoverable Operation Attempt=1
[Thu APR 30 14:43:32 2015] [26770:14544] [info] ajp_service::jk_ajp_common.c (1941): (Tomcattaohandan) Sending request to Tomcat failed, Recoverable Operation attempt=2
[Thu APR 30 14:43:32 2015] [26770:14544] [ERROR] AJP_SERVICE::JK_AJP_COMMON.C (1953): (Tomcattaohandan) connecting to Tomcat failed. Tomcat is probably not started or was listening on the wrong port
[Thu APR 30 14:43:32 2015] [26770:14544] [INFO] service::jk_lb_worker.c (1098): Service failed, worker Tomcattaohandan is in error state
[Thu APR 30 14:43:33 2015] [25203:14544] [info] ajp_send_request::jk_ajp_common.c (1215): (Tomcatchangbao) error sending request. Would try another pooled connection
[Thu APR 30 14:43:33 2015] [25203:14544] [info] AJP_SEND_REQUEST::JK_AJP_COMMON.C (1241): (Tomcatchangbao) all endpoints is disconnected
[Thu APR 30 14:43:33 2015] [25203:14544] [info] ajp_send_request::jk_ajp_common.c (1244): (Tomcatchangbao) Increase the backend idle connection Timeout or the Connection_pool_minsize
[Thu APR 30 14:43:33 2015] [25203:14544] [info] ajp_service::jk_ajp_common.c (1941): (Tomcatchangbao) Sending request to Tomcat failed, recoverable Operation Attempt=1
[Thu APR 30 14:43:33 2015] [25483:14544] [ERROR] AJP_CONNECTION_TCP_GET_MESSAGE::JK_AJP_COMMON.C (951): (TOMCAT1) can ' t receive the response Message from Tomcat, network problems or Tomcat (127.0.0.1:8009) was down (errno=104)
[Thu APR 30 14:43:33 2015] [25483:14544] [ERROR] AJP_GET_REPLY::JK_AJP_COMMON.C (1592): (TOMCAT1) Tomcat is down or refused connection. No response have been sent to the client (yet)
[Thu APR 30 14:43:33 2015] [25483:14544] [info] ajp_service::jk_ajp_common.c (1902): (TOMCAT1) receiving from Tomcat failed, recoverable operation a Ttempt=1
[Thu APR 30 14:43:33 2015] [25483:14544] [info] ajp_service::jk_ajp_common.c (1941): (TOMCAT1) Sending request to Tomcat failed, recoverable Operati On attempt=2
[Thu APR 30 14:43:33 2015] [25483:14544] [ERROR] AJP_SERVICE::JK_AJP_COMMON.C (1953): (TOMCAT1) connecting to Tomcat failed. Tomcat is probably not started or was listening on the wrong port
[Thu APR 30 14:43:33 2015] [25483:14544] [INFO] service::jk_lb_worker.c (1098): Service failed, worker TOMCAT1 is in error state

Apache JK Tomcat Cluster problem