load balancing percona with haproxy
<p>I am trying to configure ha-proxy for percona DB with 3 different nodes. My configuration goes as follows-</p>

<pre><code>backend mysql_backend
mode tcp
option tcplog
balance leastconn
option httpchk default-server port 9200 inter 5s downinter 10s  rise 3 fall 2 maxconn 256
server  percona1  percona-1:3306 check port &lt;port_num&gt; inter 12000 rise 3 fall 3 maxconn 450
server  percona2 percona-2:3306 check port &lt;port_num&gt; inter 12000 rise 3 fall 3 maxconn 450 backup
server  percona3 percona-3:3306 check port &lt;port_num&gt; inter 12000 rise 3 fall 3 maxconn 450 backup
</code></pre>

<p>In the above configuration,<code>*maxconn 450*</code> specifies the maximal number of concurrent connections that will be sent to this server1 i.e. percona1. Now interesting thing that pop up in my mind, what if </p>

<ol>
<li><p>number of connection reach to 450 and another request comes?? Will the 451st request will be queued or it will be forwarded to percona2/percona3(which is a back up server in case percona1 fail but here percona1 did not fail but reach to limit)</p></li>
<li><p>Percona1(my.conf) configured such as it can handle as many as 250  connection at a time but from proxy server, it gets more than 250 like 450 as it is configured in proxy server.</p></li>
</ol>

<p>My question is what will happen in the above scenarios??</p>

<p>I have read documentation however i dint get any clear information. Help will be much appreciated.</p>