Re: TCP failed connection attempts

Sergey Malinin <hell@xxxxxxxxxxx> · Thu, 27 Mar 2014 12:44:21 +0300



    On 27.03.14, 10:52, Dan Van Der Ster
      wrote:

    
        On 26 Mar 2014 at 21:33:06, Sergey Malinin (hell@xxxxxxxxxxx)
        wrote:
      
        
                          This is typical (output from netstat -s):
                        
                          
                              50329019 active
                            connections openings
                              15218590 passive
                            connection openings
                              44167087 failed
                            connection attempts
                          

              Taking into account that presumably
                you don't have anything besides osd daemon running on
                the machine, i would say that this is extraordinarily
                large

              number indicating that something is
                definitely going wrong.
          
      
      This was my thinking as well. I am seeing this on a test
        cluster with very few real clients, so most of the connect
        attempts should be replication from other OSDs.
    
    This figure represents connections initiated locally, i.e.
    replication *to* other osds. 

    
      The suggested sysctl changes didn’t stop the failed conn
        attempts from increasing. I’m going to keep looking around…
    
    sysctl has nothing to do with that since those are just counters.
    You can debug failed connections by logging connection resets:

    iptables -I INPUT -p tcp -m tcp --tcp-flags RST RST -j LOG

    
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