Cookie persistence and intermittent node failure

monitor cookie_app_monitor {
   defaults from http
   interval 30
   timeout 91
   partition App1
}

profile persist cookie_app_persist_profile {
   defaults from cookie
   mode cookie
}

profile tcp cookie_app_lan-optimized_tcp_profile {
   defaults from tcp-lan-optimized
}
profile tcp cookie_app_wan-optimized_tcp_profile {
   defaults from tcp-wan-optimized
}

node 10.1.2.11 {
   screen cookie_app_node1
}
node 10.1.2.12 {
   screen cookie_app_node2
}

pool cookie_app_pool {
   lb method member least conn
   monitor all tcp_half_open
   members {
      10.10.2.11:http {
         priority 1
      }
      10.10.2.12:http {
         priority 1
      }
   }
}

virtual cookie_app_virtual_server {
   snat automap
   pool cookie_app_pool
   destination 10.10.3.22:http
   ip protocol tcp
   persist cookie_app_persist_profile
   profiles {
      cookie_app_lan-optimized_tcp_profile {
         serverside
      }
      cookie_app_wan-optimized_tcp_profile {
         clientside
      }
      microsoft_iis_http-wan-optimized-compression_shared_http {}
   }
}