> -----Original Message----- > From: Chuck Caldarale <n82...@gmail.com> > Sent: Monday, June 24, 2024 1:40 PM > To: Tomcat Users List <users@tomcat.apache.org> > Subject: Re: Isolating the Root Cause of "Connection Refused" > > > > On Jun 24, 2024, at 15:36, Eric Robinson <eric.robin...@psmnv.com> wrote: > > > >> -----Original Message----- > >> From: Chuck Caldarale <n82...@gmail.com> > >> Sent: Monday, June 24, 2024 1:29 PM > >> To: Tomcat Users List <users@tomcat.apache.org> > >> Subject: Re: Isolating the Root Cause of "Connection Refused" > >> > >> > >>> On Jun 24, 2024, at 15:19, Eric Robinson <eric.robin...@psmnv.com> > wrote: > >>> > >>> We have a tomcat server that is not that busy. It has 100 tomcat > >>> instances > >> running, but it handles a few hundred connections per second total, > >> across all of them. It intermittently rejects connection attempts to > >> listening tomcats. The server is running Rocky 8, has 48 cores (about > >> 15-40% utilized), 1T RAM (400G free), with NVME storage. 'sar' shows > almost 0% iowait. > >>> > >>> During production: > >>> > >>> * /proc/sys/net/netfilter/nf_conntrack_count shows anywhere from 100K > to > >> 250K connections > >>> * /proc/sys/net/netfilter/nf_conntrack_max is set to 2M. > >>> * netstat -an|wc -l usually shows 90-150K connections > >>> > >>> Obviously, the TCP stack must be running into some resource > >>> limitation, or > >> some kind of race condition. I've been working the issue for hours > >> and days, without success. How can I determine exactly why the > >> tomcats intermittently reject connections? > >> > >> > >> Perhaps some of the Tomcat processes are occasionally running out of > >> file descriptors? > >> > > > > Great thought. Wouldn't tomcat log a message somewhere if that were the > case? > > > No - Tomcat would never see the request and would have no knowledge that the > OS blocked the connection attempt. >
But the OS should log something, I assume? I don't see anything in dmesg or messages. > - Chuck > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org Disclaimer : This email and any files transmitted with it are confidential and intended solely for intended recipients. If you are not the named addressee you should not disseminate, distribute, copy or alter this email. Any views or opinions presented in this email are solely those of the author and might not represent those of Physician Select Management. Warning: Although Physician Select Management has taken reasonable precautions to ensure no viruses are present in this email, the company cannot accept responsibility for any loss or damage arising from the use of this email or attachments. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
