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On 11/16/11 8:47 AM, Pid * wrote: > Tomcat 6.0.32, HTTPD (worker mpm) 2.2.19, mod_jk 1.2.31. > > If ThreadsPerChild is 60 and ServerLimit is 10, MaxClients is 600, > how many connections, at peak, will be made to 20 Tomcat > instances? - From httpd docs: MaxClients: For threaded and hybrid servers (e.g. beos or worker) MaxClients restricts the total number of threads that will be available to serve clients. The default value for beos is 50. For hybrid MPMs the default value is 16 (ServerLimit) multiplied by the value of 25 (ThreadsPerChild). Therefore, to increase MaxClients to a value that requires more than 16 processes, you must also raise ServerLimit. ServerLimit: With worker use this directive only if your MaxClients and ThreadsPerChild settings require more than 16 server processes (default). Do not set the value of this directive any higher than the number of server processes required by what you may want for MaxClients and ThreadsPerChild. So if MaxClients is 600 and ThreadsPerChild is 60 then you can't have more than 10 processes each with 60 threads. If you want more than 16 server processes (which it looks like you don't need), then you'll need to set ServerLimit to something higher than it's default for worker which appears to be 16. I'm not sure you need ServerLimit at all. If you have 20 TCs on the back end, then mod_jk will have to open 20 * 600 = 12000 connections at peak, if my math is correct. That's only 600 connections per TC, or course, but you may have trouble with creating that many connections from the proxy. If you have more than one worker, then the number of Tomcat instances is essentially multiplied. So, if you have 20 TC backends each with 2 workers assigned to them, then you'll 24000 connections instead. > Will this change If Tomcat instances start failing? Probably not -- mod_jk will just retire the connection and create a new one. If you are having load problems, you might make things worse with all this connection churn. - -chris -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.17 (Darwin) Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk7D6mAACgkQ9CaO5/Lv0PCwSACfaDMyMVnj5GhMEhRgnH07R2Hh /EEAnAyqpjnZSDmbnZrHxwC5BMSC1tJ5 =vpRW -----END PGP SIGNATURE----- --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
