Tcpcopy,an online request replication tool fit for nginx

[wangbin579]

Name:
    tcpcopy
    It is a request replication tool and is mainly for testing tasks
using netlink and raw sockets


Description:
    It can help you find bugs in your online project without actually
being online. 
    And it can also be used to test the stress that a system could
endure.

    For example, if your system already has "memcached" subsystem and
you want to 
    use "membase" to replace it, tcpcopy can assist you to test
"membase". While your 
    old memcached system is still running online, tcpcopy could copy the
flow of packets 
    from memcached to membase. From the point view of membase, the flow
is accessing 
    membase(just like membase online), and it will not affect memcached
at all except 
    network bandwidth and a little cpu load.


Functionalities：
    1) Distributed Stress Test
        You can use online data to test the stress that your target
machine can endure. It is better 
        than apache ab tool and you can find bugs that only occur during
high-stress situations.
    2) Hot Backup
        It is very suitable for backup tasks if connections are
short-lived and the request loss rate
        is very low(1/100000).
    3) Normal Online Test
        You can find whether the new system is stable and find bugs that
only occur in actual 
        online environments.
    4) Comparison Test
        For example, you can use tcpcopy to compare the performances of
apache and nginx.


Characteristics：
    1)real time
    2)realistic
    3)efficient
    4)easy to use
    5)distributed
    6)significant

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,217680,217954#msg-217954