proxool连接池

最近公司在做的一个项目是分布式的,分为一个数据库服务器,和多个应用服务,所有的应用服务部署后都共享这一台数据服务器中的数据,所以部署后,每个应用服务都有一个连接池,通过连接池访问数据服务器上数据库中的数据,连接池采用proxool,但现在不稳定,会出现些许异常,有时候下面的某一个应用服务从连接池中获取数据连接connection就会发生这样的异常,我调试调了好久,总不能调好,不知道何原因,
其异常信息是:Prototype com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection,  message from server: "Too many connections".
请牛人指点指点.下面是我连接池的具体配置:
<?xml version="1.0" encoding="UTF-8"?>
<something-else-entirely>
<proxool>
<alias>BAASPool</alias>
<driver-url>
jdbc:mysql://10.71.136.159:3306/baas?useUnicode=true&amp;characterEncoding=utf8
</driver-url>
<driver-class>com.mysql.jdbc.Driver</driver-class>
<driver-properties>
<property name="user" value="root" />
<property name="password" value="toor" />
</driver-properties>
<minimum-connection-count>20</minimum-connection-count>
<maximum-connection-count>100</maximum-connection-count>
<maximum-active-time>300000</maximum-active-time>
<maximum-connection-lifetime>
10800000
</maximum-connection-lifetime>
<simultaneous-build-throttle>80</simultaneous-build-throttle>
<house-keeping-sleep-time>15000</house-keeping-sleep-time>
<house-keeping-test-sql>
select CURRENT_DATE
</house-keeping-test-sql>
<statistics>1m,15m,1d</statistics>
<statistics-log-level>DEBUG</statistics-log-level>
</proxool>
</something-else-entirely>