changing through ndd is permanent ?

[Shivkumar]

Hi Sirs,

We have a setting on web server as
ndd -get /dev/tcp tcp_conn_request_max
1024
i am seeing around 25-30 TIMEWAIT connections when viewed through netstat -an command.

I want to change it to 4096 using the command
ndd -set /dev/tcp tcp_conn_request_max 4096

If i execute this command as root (powerbroker), will this be a permanent change or would i need to put in some configuration file ?

Thanks,
Shiv
Thanks,
Shiv

[Mel Burslan · Accepted solution]

In order to make your changes permanent with ndd, you will need to put them into the file

/etc/rc.config.d/nddconf

in the form of

TRANSPORT_NAME[0]=tcp
NDD_NAME[0]=tcp_conn_request_max
NDD_VALUE[0]=4096

the value in square brakets must be unique for each parameter you want to place in this file. So, if you have parameters set, prior to you editing this file, use the next number in the sequence.

Hope this helps.

[Mahesh Kumar Malik]

Hi Shiv

Restart the network services after making changes in config file:

#/sbin/init.d/net stop
#/sbin/init.d/net start

Regards
Mahesh

[Devender Khatana]

Hi,
MK Malik---->>>Restart the network services after making changes in config file:


Restarting the services are not required as "ndd -c " will reread these entries and apply all tunables online.

HTH,
Devender

[Bill Hassell]

Note: there is a bug in ndd at certain revisions where the ndd -c option does not work. Be sure to add the latest patch for ndd. Then, be sure to test that the setting does indeed change. Use the -get option to read the current value:

ndd -get /dev/tcp tcp_conn_request_max

Now change the nddconf file and run ndd -c to re-read (and set) the values. Now run -get again. The value should change. ndd values change immediately, whether done with the -set option or the -c option. By using -c, you are also verifying that the option(s) in nddconf are correct and will be read upon reboot.

[Babu A]

Hi Shiv,

You should make entry in /etc/rc.config.d/nddconf. The file should like as follows.

TRANSPORT_NAME[0]=tcp
NDD_NAME[0]=tcp_conn_request_max
NDD_VALUE[0]=4096

Regards,

Babu

[rick jones]

FWIW, there is no correlation between connections in TIME_WAIT and the setting of tcp_conn_request_max. Tcp_conn_request_max is _not_ the maximum number of TCP connections on the system. Rather, it is the maximum number of connections that can be queued to a listen socket. You would increase tcp_conn_request_max (and the applications parameter to the listen() call) when you see connections dropped due to full queue in the output of netstat -p tcp.

25-30 connections in TIME_WAIT is not a big deal and in and of itself does not suggest any need to tune the networking stack.

ftp://ftp.cup.hp.com/dist/networking/briefs/annotated_ndd.txt
ftp://ftp.cup.hp.com/dist/networking/briefs/annotated_netstat.txt