-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 Bruce,
On 3/5/14, 1:11 PM, Bruce Weertman wrote: > We have a load balancer talking with tomcat’s running on multiple > backend tomcat servers. The tomcats are running web service > applications. In doing testing, and as reported by customers, we > occasionally see refused connections. Not real often, but enough > to be a head ache. > > We’re not sure where the problem is coming from. Suspects include > (1) firewall, (2) load balancer (3) tomcat and perhaps the (4) the > web app. The volume of traffic is so high, that it becomes a > needle in a hay stack issue. Can you describe your setup in a bit more detail? What kind of lb? How many of them? Any fronting web server(s)? How many? How many Tomcat instances? What is/are your <Connector> configuration(s)? > We are using the BIO connector and everything is HTTP. Our typical > hit rates are dozens per second. Tomcat can certainly handle that kind of thing. If you have long wait-times for your webapp, you might not be able to keep up. > In my experimentation with Tomcat, if it runs out of threads and > the accept queue fills, there is no indication in (for example) > catalina.out.> (see acceptCount and maxConnections in > http://tomcat.apache.org/tomcat-7.0-doc/config/http.html) Tomcat usually complains if you run out of threads. > In production maxConnections is the default of 200, but when > looking at the number of connections being processed by tomcat it’s > rarely more than a couple dozen per instance. There’s always the > possibility that it occasionally spikes. What is the resolution of the data you have? Are you sampling with some regularity? > Anyway, the question is: Is there any good way to see if tomcat > is going into a state where it’s not accepting connections? How > would would I see this? Is it possible to see this ? Sure: connect to a specific Tomcat. If you get a "connection refused", then you are in this state. Your load balancer should have a setting where you can choose a back-end server explicitly if you want to go through the lb, or you can just contact one directly. - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCAAGBQJTF27qAAoJEBzwKT+lPKRYaF8P/iANR7Xzvi/D9LA40TmS2XB2 GsvI2mchm580mQF0mhn2sgcpytCc2RPTRKeWw2RgSsZNoOMH8Bnrdq3HLAD0cKlF qv398kDvRN08GLh4qZSsfVT/XOQHSfLOf84ptB1otGyn4IqDc3sWe0lmtOPoO8uJ SQeZcn5qhhHcyF6Nn6sRs0vTngR6gSr4eGroGF9QSZIyXPyIo5FjF4tDNfUhl2wf wAl8FRrHpNDaCgk49frV/Y6eIMETVUIr7JV+viqE1a497oE0Iok5n2b79EOAPGwU eDJ+JiBchqe+Qwy4CMCJctEKMagHXSxslY6xO/B7L3hK1d0Zo11zcLMtXx7C6aaa z7uRsge+xlASxHhifw2/LkQuKBEzLEtPhUMUn6uxiATew5B/DqTgREEGpf9laC2o egKrVR2i46iD/71y3fMWL+xqbz2i/Y5zsnNBQiDdt/YepZ+/k88VbPihPs8EavqG U8d5DnTtl0wQvvbdv7KORAIYLP545pHiDcUEXEqHjABECoPIDqDoDmVLuq3mhZxL q6BsCrWkU591CWme411IS95iLHY3W1a/9+INVYPZUB/99Eej6ntlvalpxyckAaPZ cAc+dnXD03YedfAczmU/5jDlZEJezAgbUdtNaECmXtahtDF61Ew5yTdfRXq/LqXY JK7aCZaJnbhtQQGSuO8J =ZEI9 -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
