max socket connections

[Devesh Pant_1]

Hello Gurus,
is there a way to find out the maximum number of socket connections that a server can have?

We have some servers that have multiple netbackup connections and also multiple autosys connections. Some of the connections are timing out/ dropping.

Any help would be greatly appreciated

thanks
DP

[Bill Hassell · Accepted solution]

Network sockets require file handles so the kernel parameter nfile controls how many sockets can be opened. Since nfile governs all files (disk filesystems, network filesystems, network sockets), you'll need to monitor thye usage of nfile with sar -v 1, or use Glance. Also look at syslog.log to see if error messages have been recorded that show all files have been used.

[Arunvijai_4]

Hi DP,

I believe, it should be 4096 from a single program. Also, check out this thread for great resource : http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=947149

-Arun

[rick jones]

Depending on the way the server's applications are written, one may also want to consider maxfiles/maxfiles_lim for the per-process limits on file descriptors, and nproc for the limits on the number of processes.

The main point from all the posts thusfar though is that there is nothing in HP-UX's "networking" implementation in and of itself that limits the number of sockets, nor the number of TCP connections one can have.

There are some theoretical limits on the number of concurrent TCP connections between pairs of IP addresses. They fall-out from TCP connections being "named" by the four-tuple of local and remote IP address and local and remote port number.