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Accepted
Sparsh Gupta
Asked: 2011-02-08 12:57:33 +0800 CST

Very Large number of connections in TIME_WAIT state; Server is slow, ipconntrac

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I have a nginx server with load balancing and reverse proxy. Right now its behing another nginx but very soon I plan to make it front, where it will receive TCP connections from clients directly at a rate of 500req/second

I am having some big troubles with the server. I have pasted my configurations here and I am kinda sure that the problem is with ipconntrac and similar things which are alient to me

http://paste.org/pastebin/view/28543

root@load_balancer:/proc/sys/net/ipv4# netstat -an|awk '/tcp/ {print $6}'|sort|uniq -c
     67 CLOSING
    727 ESTABLISHED
    173 FIN_WAIT1
    183 FIN_WAIT2
     19 LAST_ACK
      5 LISTEN
    447 SYN_RECV
      1 SYN_SENT
  27970 TIME_WAIT

Its a ubuntu machine with mainly nginx (load balancer and reverse proxy) installed.

It surely isnt great. Can you help me understand whats going on and how can I fix it. This is my live server and I am sure its in a bad shape right now. Any document or commands to fix this, or settings I should make to make this better and reduce time wait and fin_wait1/2 better would be awesome.

nginx

1 Answers

  1. Best Answer

    Try the following:

    echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle
echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse

    Probably it will help to reduce the number of TIME_WAIT connections. You can also make these changes permanent in /etc/sysctl.conf:

    net.ipv4.tcp_tw_reuse=1
net.ipv4.tcp_tw_recycle=1
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