ubuntu:
####1.single file max handler:

erlang:system_info (check_io).

{max_fds,1024} shows how many handler you can set at one file.
You can change that like this:

sudo vim /etc/security/limits.conf

add two rows:
* soft nofile 100000
* hard nofile 100000
and restart your computer. It works! ye~ :). ####2.computer max port limit:

erlang:system_info (port_limit).

it shows max port limit of your computer, you can add +Q behind 'erl' like:

erl +Q 100000

to change it. ####3.computer port range: if you don't need stress test then you can skip this step.

su  
echo "1024 65535" > /proc/sys/net/ipv4/ip_local_port_range  
cat /proc/sys/net/ipv4/ip_local_port_range  

rebar compile
erl

gatling:start().

then you can see some log in browser's console. I only test in chrome, :).