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<TITLE>RE: [Beowulf] Concurrently open sockets limit on Linux system</TITLE>
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<P><FONT SIZE=2>Joe - good ideas!</FONT>
</P>
<P><FONT SIZE=2>As a debugging step we even ran the LM daemon as root, ulimit -a reports a file limit of 65535...</FONT>
</P>
<P><FONT SIZE=2>It's a permanently running daemon, not going through xinetd and it, annoyingly, produces no logs or sends anything to syslog.</FONT></P>
<P><FONT SIZE=2>Thanks for your thoughts...</FONT>
<BR><FONT SIZE=2>Simon</FONT>
</P>
<BR>
<BR>
<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Joe Landman [<A HREF="mailto:landman@scalableinformatics.com">mailto:landman@scalableinformatics.com</A>]</FONT>
<BR><FONT SIZE=2>Sent: 2007 Jun 17 2:52 PM</FONT>
<BR><FONT SIZE=2>To: Galton, Simon</FONT>
<BR><FONT SIZE=2>Cc: 'beowulf@beowulf.org'</FONT>
<BR><FONT SIZE=2>Subject: Re: [Beowulf] Concurrently open sockets limit on Linux system</FONT>
</P>
<BR>
<P><FONT SIZE=2>Hi Simon</FONT>
</P>
<P><FONT SIZE=2>Galton, Simon wrote:</FONT>
</P>
<P><FONT SIZE=2>> (according lsof on the system running the license manager) seems to hold </FONT>
<BR><FONT SIZE=2>> a socket open during the duration of the job.</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> We want to run a couple of hundred of these jobs on our cluster, but </FONT>
<BR><FONT SIZE=2>> after job 126 the client can no longer connect to the license manager. </FONT>
</P>
<P><FONT SIZE=2>This seems to suggest somewhere that there is a 128 socket limit on the </FONT>
<BR><FONT SIZE=2>service. How is the license manager run? What does</FONT>
</P>
<P> <FONT SIZE=2>limit</FONT>
</P>
<P><FONT SIZE=2>or</FONT>
</P>
<P> <FONT SIZE=2>ulimit -a</FONT>
</P>
<P><FONT SIZE=2>tell you for the user that the license manager runs as? Any notes in </FONT>
<BR><FONT SIZE=2>system logs?</FONT>
</P>
<P><FONT SIZE=2>> The server hosting the license manager is otherwise fine, and you can </FONT>
<BR><FONT SIZE=2>> continue to perform network-based operations on and against it...</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> The vendor feels that they have not coded a specific limit; I'm </FONT>
<BR><FONT SIZE=2>> wondering if it's file descriptors or somesuch. I raised the limit of </FONT>
<BR><FONT SIZE=2>> FDs on the system to 65000+ and verified that the change took effect; no </FONT>
<BR><FONT SIZE=2>> change to the applications behaviour. It's a c-based app, compiled with </FONT>
<BR><FONT SIZE=2>> gcc on a Fedora Core 6 system, I believe.</FONT>
</P>
<P><FONT SIZE=2>Doesn't sound like an FD limit, but as a socket limit. Older inetd's </FONT>
<BR><FONT SIZE=2>had something like 20-40 connections per process. If you are serving </FONT>
<BR><FONT SIZE=2>this through xinetd or similar, you might be able to raise these limits.</FONT>
</P>
<P><FONT SIZE=2>Joe</FONT>
</P>
<P><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Any thoughts?</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> Simon</FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
<BR><FONT SIZE=2>> </FONT>
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<P><FONT SIZE=2>-- </FONT>
</P>
<P><FONT SIZE=2>Joseph Landman, Ph.D</FONT>
<BR><FONT SIZE=2>Founder and CEO</FONT>
<BR><FONT SIZE=2>Scalable Informatics LLC,</FONT>
<BR><FONT SIZE=2>email: landman@scalableinformatics.com</FONT>
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