topic Re: ndd parameters in Operating System - HP-UX

ndd parameters

KPS — Tue, 07 Jul 2009 14:57:54 GMT

Hi,

I have a question or two about TCP Transport parameters. For our application, we were told by App Vendor and HP that the following ndd parameters should be changed from their default value to some specific values that would better suit our large environment. Below are the TCP Transport parameters and current settings in /etc/rc.config.d/nddconf

TRANSPORT_NAME[0]=tcp
NDD_NAME[0]=tcp_recv_hiwater_def
NDD_VALUE[0]=262144
TRANSPORT_NAME[1]=tcp
NDD_NAME[1]=tcp_xmit_hiwater_def
NDD_VALUE[1]=262144
TRANSPORT_NAME[2]=tcp
NDD_NAME[2]=tcp_recv_hiwater_lfp
NDD_VALUE[2]=262144
TRANSPORT_NAME[3]=tcp
NDD_NAME[3]=tcp_xmit_hiwater_lfp
NDD_VALUE[3]=262144
TRANSPORT_NAME[4]=sockets
NDD_NAME[4]=socket_udp_rcvbuf_default
NDD_VALUE[4]=262144
TRANSPORT_NAME[5]=sockets
NDD_NAME[5]=socket_udp_sndbuf_default
NDD_VALUE[5]=262144

What I'm interested in right now is what the default Transport Value is for each of these parameters above. Would anyone by chance know how to obtain the default settings for the above or by chance know what they might be?

Here is some more info of system type and OS:

OS= HP-UX 11.23 (ia64)
System Type= BL870

Thanks in advance,

KPS

Re: ndd parameters

Patrick Wallek — Tue, 07 Jul 2009 15:10:39 GMT

To get the default value run the command 'ndd -h ' for each parameter.

For example:

$ ndd -h tcp_recv_hiwater_def

tcp_recv_hiwater_def:

The maximum size for the receive window. [4096,-]
Default: 32768 bytes

Re: ndd parameters

Mel Burslan — Tue, 07 Jul 2009 15:27:02 GMT

here are my values from a recently installed (and never been messed with ndd settings) 11.23 system: (look at lines starting with -->

NDD_NAME[0]=tcp_recv_hiwater_def
NDD_VALUE[0]=262144
-->32768

NDD_NAME[1]=tcp_xmit_hiwater_def
NDD_VALUE[1]=262144
-->32768

NDD_NAME[2]=tcp_recv_hiwater_lfp
NDD_VALUE[2]=262144
-->65536

NDD_NAME[3]=tcp_xmit_hiwater_lfp
NDD_VALUE[3]=262144
-->65536

NDD_NAME[4]=socket_udp_rcvbuf_default
NDD_VALUE[4]=262144
-->65535

NDD_NAME[5]=socket_udp_sndbuf_default
NDD_VALUE[5]=262144
-->65535

Hope this helps

Re: ndd parameters

Steven E. Protter — Tue, 07 Jul 2009 15:30:24 GMT

Shalom,

I would do an install of 11.23 on a system and take a look at /etc/rc.config.d/nddconf

That is how I'd find out the defaults.

The man pages don't seem to say anything.

SEP

Re: ndd parameters

Patrick Wallek — Tue, 07 Jul 2009 15:36:09 GMT

>>I would do an install of 11.23 on a system
>>and take a look at /etc/rc.config.d/nddconf
>>That is how I'd find out the defaults.

Then you wouldn't find anything. The nddconf file is empty by default.

>>The man pages don't seem to say anything.

Really? I thought it actually provided useful information. I guess you just missed the information about the '-h' option:

ndd -h
When parameter is specified, a detail description of the parameter, along with its minimum, maximum, and default value are displayed. If no parameter is specified, it displays all supported and unsupported tunable parameters.

Re: ndd parameters

KPS — Tue, 07 Jul 2009 16:17:12 GMT

ndd -h worked perfectly, thanks everyone for you input on this.

/KPS

Re: ndd parameters

KPS — Tue, 07 Jul 2009 16:18:02 GMT

pts assigned.

Re: ndd parameters

rick jones — Tue, 07 Jul 2009 23:19:52 GMT

Not that I'm 100% fond of the current HP-UX defaults (32768 has been the default TCP socket buffer size since 10.20 if I recall correctly) but did the app vendor/HP give specific reasons for the values they requested? And exactly what do you mean by "large environment?" Do you mean you have large bandwidthXdelay paths in your network, or something else?

Re: ndd parameters

KPS — Wed, 08 Jul 2009 09:09:13 GMT

I'm in the process of going back to the vendor to find out exactly why they suggested these values. I believe it's because of the bandwith and type of TCP packets that they expected to see between our Application and Database tier servers using this App.