I have a haproxy setup on centos 6.4 and now i have to test it with maximum number of supported connections by it,

When i increase the maxconn in HAProxy it gives the following errror,

Starting haproxy: [WARNING] 121/130735 (21932) : [/usr/sbin/haproxy.main()] Cannot raise FD limit to 134529346.
[WARNING] 121/130735 (21932) : [/usr/sbin/haproxy.main()] FD limit (1024) too low for maxconn=67264666/maxsock=134529346. Please raise 'ulimit-n' to 134529346 or more to avoid any trouble.
[ALERT] 121/130735 (21932) : [/usr/sbin/haproxy.main()] Cannot fork.
[FAILED]

and when i try to increase the ulimit to 2 million or more then i m not able to login that centos machine.

how we can achieve this, to maximize the ulimit and maxconn more than million or billion ?

Thanks..!

Try this: http://www.cyberciti.biz/faq/linux-i...of-open-files/

I tried to set ulimit 2000000 but its not working . it blocks ssh login for all users.

Have you tried to set /proc/sys/fs/file-max ?

cat /etc/sysctl.conf |grep "fs.file-max"