I finally found that, it's because the back-end Apache server is not enough,
when I added more Apache servers in the back-end, haproxy can handle more
requests per second. Thanks guys. I think I can close this case.
> Date: Wed, 15 Aug 2012 10:28:40 +0200
> Subject: Re: encounter a problem when testing HAProxy
> From: bed...@gmail.com
> To: jerrythrill...@hotmail.com
> CC: mandm_z...@yahoo.com; haproxy@formilux.org
>
> Hi,
>
> Amol forgot to mention it, but the conntrack table full should appear
> on the LB, not on the servers.
>
> Could you paste here a few log lines from when the problem occurs?
> HAProxy logs are very verbose and we may find something here.
>
> Which version of HAProxy are you running?
>
> cheers
