loosing connectivity with jboss on ajp

During performance test of a jboss cluster (no session preserved) we issue some problem with mod_cluster, specially when apache try to access to the jboss instance through ajp
And we don't see where the problem come from (JBoss configuration, mod_cluster configuration, bug).

We don't use Multicast to discover nodes of the cluster

[Thu Jul 22 15:13:14 2010] [debug] mod_manager.c(1416): manager_trans STATUS
[Thu Jul 22 15:13:14 2010] [debug] mod_manager.c(1929): manager_handler STATUS (D:/) processing: "JVMRoute=svayn02a&Load=90"
[Thu Jul 22 15:13:14 2010] [debug] proxy_util.c(1999): proxy: ajp: has acquired connection for (10.231.242.19)
[Thu Jul 22 15:13:14 2010] [debug] proxy_util.c(2055): proxy: connecting ajp://10.231.242.19:8009/ to 10.231.242.19:8009
[Thu Jul 22 15:13:14 2010] [debug] proxy_util.c(2153): proxy: connected ajp://10.231.242.19:8009/ to 10.231.242.19:8009
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(1194): ajp_cping_cpong: Done
[Thu Jul 22 15:13:14 2010] [debug] proxy_util.c(2017): proxy: ajp: has released connection for (10.231.242.19)
[Thu Jul 22 15:13:14 2010] [debug] mod_manager.c(1970): manager_handler STATUS OK
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(943): get_balancer_by_node balancer NOT found
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(943): get_balancer_by_node balancer NOT found
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(943): get_balancer_by_node balancer NOT found
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(943): get_balancer_by_node balancer NOT found
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(943): get_balancer_by_node balancer NOT found
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(943): get_balancer_by_node balancer NOT found
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(943): get_balancer_by_node balancer NOT found
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(943): get_balancer_by_node balancer NOT found
[Thu Jul 22 15:13:14 2010] [debug] mod_manager.c(1416): manager_trans STATUS
[Thu Jul 22 15:13:14 2010] [debug] mod_manager.c(1929): manager_handler STATUS (D:/) processing: "JVMRoute=svayn01a&Load=90"
[Thu Jul 22 15:13:14 2010] [debug] proxy_util.c(1999): proxy: ajp: has acquired connection for (10.231.242.18)
[Thu Jul 22 15:13:14 2010] [debug] proxy_util.c(2055): proxy: connecting ajp://10.231.242.18:8009/ to 10.231.242.18:8009
[Thu Jul 22 15:13:14 2010] [debug] proxy_util.c(2153): proxy: connected ajp://10.231.242.18:8009/ to 10.231.242.18:8009
[Thu Jul 22 15:13:14 2010] [debug] mod_proxy_cluster.c(1194): ajp_cping_cpong: Done
[Thu Jul 22 15:13:14 2010] [debug] proxy_util.c(2017): proxy: ajp: has released connection for (10.231.242.18)
[Thu Jul 22 15:13:14 2010] [debug] mod_manager.c(1970): manager_handler STATUS OK

Configuration :

common.conf :

LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
LoadModule slotmem_module modules/mod_slotmem.so
LoadModule manager_module modules/mod_manager.so
LoadModule proxy_cluster_module modules/mod_proxy_cluster.so

[...]

SSLSessionCache none
MaxRequestsPerChild 5000
#MaxRequestsPerChild 0
MaxMemFree 512
#JkWatchdogInterval 60
ThreadLimit 300
ThreadsPerChild 300

svayn.conf :

PidFile var/svayn/httpd.pid
Include conf/common.conf
Listen 10.231.241.243:8031 http
#Listen 10.231.241.243:8444 https
MemManagerFile d:/Apache/var/svayn/manager
ErrorLog d:/logs/apache/svayn/error.log
#CustomLog d:/logs/apache/svayn/access.log combined
NameVirtualHost 10.231.241.243:8031
#NameVirtualHost 10.231.241.243:8444

#SSLCertificateFile d:/certs/svayn/cert.crt
#SSLCertificateKeyFile d:/certs/svayn/cert.key

<Location />
<LimitExcept OPTIONS GET HEAD POST PUT DELETE>
Order deny,allow
Deny from all
Allow from wse0846.maafprod.e-corail.com wse0847.maafprod.e-corail.com 127.0.0.1
</LimitExcept>
</Location>

<VirtualHost 10.231.241.243:8031>
ServerName localhost
DocumentRoot d:/www/empty

<Location /cluster-status>
SetHandler mod_cluster-manager

Order deny,allow
Deny from all
Allow from 10.231.241.243 127.0.0.1
</Location>

<Location /server-status>
SetHandler server-status

Order deny,allow
Deny from all
Allow from 10.231.241.243 127.0.0.1
</Location>
</VirtualHost>

#<VirtualHost 10.231.241.243:8444>

1. ServerName localhost
2. DocumentRoot d:/www/empty
3. SSLEngine on
   #</VirtualHost>

<VirtualHost 10.231.241.243:8031>
ServerName nsiperf.maafprod.e-corail.com
ServerAlias nsiperf
DocumentRoot d:/www/svayn/
RewriteEngine on
RewriteRule ^/(index.asp)?$ /vadautodirectmaaf/SA_ProductionAutoClientDirect_FX/SA_ProductionAutoClientDirect_FX.html?destination=AccesPublicCE&entryPoint=AccesPublicDefaut&enseigne=MAAF&contexte=D4RNMAAF [NC,R=301,L]

UseAlias 1
KeepAliveTimeout 60
MaxKeepAliveRequests 0

</VirtualHost>

#<VirtualHost 10.231.241.243:8444>

1. ServerName nsiperf.maafprod.e-corail.com
2. ServerAlias nsiperf
3. DocumentRoot d:/www/svayn/
4. RewriteEngine on
5. RewriteRule ^/(index.asp)?$ /vadautodirectmaaf/SA_ProductionAutoClientDirect_FX/SA_ProductionAutoClientDirect_FX.html?destination=AccesPublicCE&entryPoint=AccesPublicDefaut&enseigne=MAAF&contexte=D4RNMAAF [NC,R=301,L]
6. SSLEngine on
   #</VirtualHost>

Thx for your help.