Howdy, It's always about tradeoffs. The poster asked for minimum interference, which I read to say if one webapp crashes, or a JSP does System.exit(), or there's malicious code running, then other webapps should not be affected. There's no way to do that if the webapps are within the same JVM, so separate tomcat instances are needed. As for the per machine part, he has a cluster already, so if you want to keep the above separation on every machine in the cluster (which I would), then that's what you have to do.
Whether it's a maintenance nightmare depends on the setup. If you use tomcat out of the box, just changing the port numbers, then probably not. We have dozens and dozens of such tomcat instances. Since they're so stable, monitored by services like Nagios, and hardly ever restarted, it hasn't been a maintenance issue for us at all. And then there's the counter-argument: if you have to explain to your CEO that one little reporting webapp brought down all your other webapps because of a bug and you didn't want to separate them in order to save a bit of maintenance time/money, well, that's a tough sell. (And I've been in that spot before ;)) Yoav Shapira Millennium ChemInformatics >-----Original Message----- >From: Marco Pas [mailto:[EMAIL PROTECTED] >Sent: Friday, January 09, 2004 3:08 AM >To: 'Tomcat Users List' >Subject: RE: Question on using Tomcat 5 in production environment; using >multiple instances or not? > >Isn't this a maintenance nightmare ? > >-----Original Message----- >From: Shapira, Yoav [mailto:[EMAIL PROTECTED] >Sent: dinsdag 6 januari 2004 14:40 >To: Tomcat Users List >Subject: RE: Question on using Tomcat 5 in production environment; using >multiple instances or not? > > >Howdy, >For minimum interference, run one instance of tomcat per application per >machine. So if you have five apps and two machines, that's ten instances >of >tomcat. > >Yoav Shapira >Millennium ChemInformatics > > >>-----Original Message----- >>From: Marco Pas [mailto:[EMAIL PROTECTED] >>Sent: Tuesday, January 06, 2004 5:30 AM >>To: '[EMAIL PROTECTED]' >>Subject: Question on using Tomcat 5 in production environment; using >>multiple instances or not? >> >>Hi, >> >>I cannot find a suitable answer on the situation and questions below: >> >>Situation: >>I want to use Tomcat in a high available environment, using 2 machines >>behind a load-balancer. >>On these machines several tomcat applications should be running. >> >>Requirements are: >>- maximum speed >>- ease of setup and maintenance >>- (possible) session clustering for failover purposes >>- when upgrading a specific application other applications should >suffer no >>interference >> >>Questions that i have are: >>- Should i run multiple instances of Tomcat on each machine, or just 1 >>instance of Tomcat per machine ? >>- Should i run a Tomcat instance per application ???? >>- Any experience in using session clustering and if this seems to hit >the >>performance ? >> >>I am searching for an infrastructure setup that suites my needs! Any >good >>hints and tips on implementing Tomcat in a production enviroment ? >> >>Greetings, >>Marco Pas >> >>This e-mail and any attachment is for authorised use by the intended >>recipient(s) only. It may contain proprietary material, confidential >>information and/or be subject to legal privilege. It should not be >copied, >>disclosed to, retained or used by, any other party. If you are not an >>intended recipient then please promptly delete this e-mail and any >>attachment and all copies and inform the sender. Thank you. >> >>--------------------------------------------------------------------- >>To unsubscribe, e-mail: [EMAIL PROTECTED] >>For additional commands, e-mail: [EMAIL PROTECTED] > > > > >This e-mail, including any attachments, is a confidential business >communication, and may contain information that is confidential, >proprietary >and/or privileged. 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