-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Vivek,
On 10/24/12 12:21 PM, vivek aggarwal wrote: > I have following understanding with regards to your trailing mail > comments ,pls do correct me if that's not correct :- > > In workers.properties (Apache end) we have directive called > "connection_pool_size" which is number of those connection that > each Apache web server child process can made to the backend > (Tomcat). So does that mean i should keep this > "connection_pool_size" value in sync with threads configured for a > given connector (http) in server.xml (Tomcat) in order to avoid > thread exhaustion limit. It's a little more complicated than that, because a threaded Tomcat can have multiple connections per child process. > Is there recommendation you have with respect to Apache-Tomcat > communication , that people like me ( naive) should keep in mind > in order to avoid any connection time out/thread exhaustion/ > response time out erorrs ?? First of all: don't set a connection_pool_size in Apache httpd: httpd will auto-detect the correct setting and use that. The logical default values would be 1 for prefork MPM and ThreadsPerChild in a threaded (worker, event, winnt, beos, netware, os2) MPM. If you want to set your connection_pool_size to something *less* than the default ThreadsPerChild that will mean that your httpd process can accept more simultaneous connections than it can route to the Tomcat backend. That might make sense for you, say, if you only expect that roughly 50% of incoming requests will need to be sent to Tomcat. In that case you might reduce your connection_pool_size to reclaim some of those resources (and reduce the peak load that any one backend Tomcat instance will experience). The equation is very simple: L = number of load balancers (httpd if you choose) Lc = number of connections each load balancer can handle T = number of backend Tomcat instances Tc = number of connections each Tomcat *must* handle Assume that all LB are connected to all TC such than any LB can forward traffic to any TC instance. Tc = L * Lc Buried in the "Lc" number is MaxClients, ThreadsPerChild, etc. and possibly the connection_pool_size if you've chosen to modify that. Just make sure that every Tomcat instance has Tc threads configured in the thread pool that serves the <Connector> you use to handle balanced traffic. Next, you have to check to make sure that your workers connection_pool_timeout is matched with your <Connector>'s connectionTimeout. I say "matched" because the value in Tomcat is expressed in ms while the connection_pool_timeout is expressed in seconds. So, just make sure you add "000" to the end in your Tomcat configuration. ;) That's the basics. - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iEYEARECAAYFAlCIOsgACgkQ9CaO5/Lv0PC+6QCfTz3dFqjqY+oTiXzIlAWAsI05 ljQAoLfuve6/8cNNZdTKCxojApD+zmMO =lKtQ -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
