My server is a FreeBSD system, I run nginx on it to proxy user requests to another real server. My problem is I can't visit my freebsd server after a while. The server is in another place, so I have to go to fix it. When the problem happens, the server can't ping another address, it can't use networks, if I reboot it and restart nginx, everything becomes normal. But after a while, it can't be visited again. I am not quite familiar with freebsd, so anyone can't help to find out the possible reason?

I think it's problem with mbufs count. There is 2 possible solutions:

You can easily check limits: Compare values LIMIT and USED in vmstat

# vmstat -z
  • Do you mean the server has used out of all mbufs? I guess this will happen if we've too many visits, but our server is not visited by many users(not more than 100 before it's down), and will mbufs be reused after a time, which means the server will recover after some time? Till now nothing changed actually. – gleery Oct 20 '09 at 8:59
  • mbufs, open files, somaxcon etc... there is too many limits in OS that you can bump in. – SaveTheRbtz Oct 20 '09 at 9:04

Check the network card as well - it might be the mbufs issue that SaveTheRbtz mentions but I've also had this problem with a network card that would inexplicably 'wedge' after a while.

  • Yeah, that's might be good suggestion. Grep /var/log/messages for something like watchdog time out and other messages from your NICs' drivers – SaveTheRbtz Oct 21 '09 at 20:58

Also check out your firewall, I had some problems with a server not forgetting about connections for a few hours. Eventually it would fill up its allotted connections and just reject everything else. If I waited it would come back. In the end I just had to disable connection tracking.

  • pf have state table that can overflow: use pfctl -sa and watch LIMITS – SaveTheRbtz Oct 20 '09 at 20:27

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.