1 Reply Latest reply: Sep 6, 2011 6:44 AM by René van Wijk RSS

    TCP Tuning Perameters.

    863710
      Dear support,

      How to find out current settings of below TCP tuning perameters for solaris 10, and how can we change or upgrade these perameters your urgent responce will be highly appreciable .

      sq_max_size
      tcp_conn_req_max_q
      tcp_conn_req_max_q0

      Thanks.
        • 1. Re: TCP Tuning Perameters.
          René van Wijk
          Problem concerning TCP has to do wait TCP connections going into TIME_WAIT state.

          To see if there are any sockets in the TIME_WAIT state you can use
          netstat -a | grep TIME_WAIT | wc -l
          When the number of TCP connections in TIME_WAIT state approach the maximum number of file descriptions your application throughput will suffer degradation

          To determine the time wait interval you can use:
          /usr/sbin/ndd /dev/tcp tcp_time_wait_interval
          Try setting this value to 60000 milliseconds
          /usr/sbin/ndd -set /dev/tcp tcp_time_wait_interval 60000
          Note that some values cannot be set using the ndd command but must be changed in /etc/system.
          To check which commands are read-write or read-only you can use
          ndd /dev/tcp \?
          On solaris 10 you might also want to change ipc1_conn_hash_size (controls the hash table to locate the
          TCP socket data structure in the kernel) by changing the /etc/system file
          set ip:ipcl_conn_hash_size=8192
          Note that the parameter tcp_conn_req_max_q controls the maximum allowed number of completed connections
          waiting to return from an accept call. This parameter should only be increased if the system is dropping connections.
          To determine the number of connection drops you can use:
          netstat -s | grep tcpListenDrop
          If the system is dropping connection try increasing the value to 1024.

          If your machine is to host a HTTP server, it is wise to increase the open file descriptor hard and soft limits, for example to 4096
          set rlim_fd_cur=4096
          set rlim_fd_max=4096
          More information on tunable parameters can be found here: http://download.oracle.com/docs/cd/E19253-01/817-0404/
          and http://download.oracle.com/docs/cd/E11035_01/wls100/perform/OSTuning.html