RE: how many tomcat in a machine?

2002-11-17 Thread Nicholas Orr
Just on this point of multiple Tomcat Instances, how does the JVM fit into
all of this.
ie does Tomcat1 use JVM1 and Tomcat2 use JVM2. Or does Tomcat1  Tomcat2 use
JVM1?

Also if you had one Tomcat Instances and 3 apps would they all share the one
instance of Log4j and its static methods or would there be three instances
of Log4j??

Nicholas Orr

-Original Message-
From: Turner, John [mailto:[EMAIL PROTECTED]] 
Sent: Friday, 15 November 2002 3:19 AM
To: 'Tomcat Users List'
Subject: RE: how many tomcat in a machine?



OK, thanks for the tip. 

John


 -Original Message-
 From: Craig R. McClanahan [mailto:[EMAIL PROTECTED]]
 Sent: Thursday, November 14, 2002 12:13 PM
 To: Tomcat Users List
 Subject: RE: how many tomcat in a machine?
 
 
 
 
 On Thu, 14 Nov 2002, Turner, John wrote:
 
  Date: Thu, 14 Nov 2002 08:27:56 -0500
  From: Turner, John [EMAIL PROTECTED]
  Reply-To: Tomcat Users List [EMAIL PROTECTED]
  To: 'Tomcat Users List' [EMAIL PROTECTED]
  Subject: RE: how many tomcat in a machine?
 
 
  A key problem to using a single Tomcat instance with multiple web 
  applications is that a problem with Tomcat or a problem
 with one single web
  app effects all the others.  In a shared server environment
 (application
  service provider, for example) you would be better off
 having multiple
  instances of Tomcat so that you can manage each instance
 separately without
  effecting the others.
 
 
 The other side of the coin is that sharing a single Tomcat
 instance saves
 a ***lot*** of memory, because the system classes are shared.
 
 You can mitigate most, but not all, of the impacts apps can
 have on each
 other by using a security manager that is appropriately 
 configured.  Glenn
 Nielsen (a Tomcat developer) has posted quite a few helpful 
 documents to
 TOMCAT-USER on how to set this up -- see the mailing list archives for
 details.  And, if you're coming to Las Vegas for ApacheCon 
 next week, his
 session on how to do this is a must attend for anyone contemplating
 setting up this sort of thing.
 
  John
 
 Craig
 
 
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RE: how many tomcat in a machine?

2002-11-17 Thread Craig R. McClanahan


On Mon, 18 Nov 2002, Nicholas Orr wrote:

 Date: Mon, 18 Nov 2002 09:13:35 +1000
 From: Nicholas Orr [EMAIL PROTECTED]
 Reply-To: Tomcat Users List [EMAIL PROTECTED]
 To: 'Tomcat Users List' [EMAIL PROTECTED]
 Subject: RE: how many tomcat in a machine?

 Just on this point of multiple Tomcat Instances, how does the JVM fit into
 all of this.
 ie does Tomcat1 use JVM1 and Tomcat2 use JVM2. Or does Tomcat1  Tomcat2 use
 JVM1?

 Also if you had one Tomcat Instances and 3 apps would they all share the one
 instance of Log4j and its static methods or would there be three instances
 of Log4j??


When people talk about running mulitple Tomcat instances, they are talking
about multiple JVMs, not one.  Out of the box, Tomcat doesn't support
multiple instances within a single JVM.

Within a single JVM, whether things like LogJ are shared or not depends on
where the classes are loaded from -- if they're inside the /WEB-INF/lib
directories, each webapp will have their own; if they are loaded from some
place like the common/lib directory, the classes will be shared.  Howver,
I understand that Log4J still supports per-webapp configuration of loggers
in the shared case if you want it.  See the Log4J docs for more info.

For more background on class loading in Tomcat, see:

http://jakarta.apache.org/tomcat/tomcat-4.1-doc/class-loader-howto.html

 Nicholas Orr

Craig


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RE: how many tomcat in a machine?

2002-11-17 Thread Jacob Kjome


 Also if you had one Tomcat Instances and 3 apps would they all share 
the one
 instance of Log4j and its static methods or would there be three instances
 of Log4j??



If you put Log4j in one of the parent classloaders that Tomcat makes 
available to webapps ( shared/lib, common/lib ) then That will be one 
instance of log4j serving many webapps.  Actually, all webapps would use 
the same default logger repository or, hierarchy unless you do specifically 
create a new logger repository for each webapp using a custom logger 
repository selector.  See the following doc on this:

http://qos.ch/containers/sc.html

I implemented a logger repository selector similar to the one described in 
that article called Log4jCRS.  You can find it here:

http://barracuda.enhydra.org/software/cvs/cvsweb.cgi/Projects/EnhydraOrg/toolsTech/Barracuda/src/org/enhydra/barracuda/log4j/

It is used in both a Log4jInit servlet and a servlet context listener 
called Log4jApplicationWatch to initialize and shutdown loggers and 
appenders, respectively.

http://barracuda.enhydra.org/software/cvs/cvsweb.cgi/Projects/EnhydraOrg/toolsTech/Barracuda/src/org/enhydra/barracuda/webapp/log4j/


Log4jCRS needs to be in a classloader visible to log4j.jar.  This means if 
Log4j.jar is in common/lib (where commons logging likes it to be) you can 
put Log4jCRS in shared/lib or common/lib.  You can't put it in WEB-INF/lib 
of your app unless you also place a copy of log4j.jar there as well because 
Log4jCRS needs to talk to classes in Log4j.jar and vice-versa.

Log4jInit and Log4jApplicationWatch *must* be in WEB-INF/lib.  This is 
because the custom logger repositories are keyed on each unique webapp 
classloader and so must be loaded in the webapp classloader of each 
individual application in order to support that condition.

You can store your log4j config file (properties or xml) in WEB-INF and 
provide something like the following to configure Log4jApplicationWatch and 
Log4jInit :


!-- Shuts down all loggers and appenders at webapp shutdown --
listener
listener-class
org.enhydra.barracuda.webapp.log4j.Log4jApplicationWatch
/listener-class
/listener


!-- == --
!--  Log4j declarations--
!-- == --
servlet
servlet-namelog4j-init/servlet-name
servlet-classorg.enhydra.barracuda.webapp.log4j.Log4jInit/servlet-class
init-param
!-- relative path to config file within current webapp --
param-namelog4j-config/param-name
param-valueWEB-INF/log4j.xml/param-value
/init-param
init-param
!-- config file re-reading specified in milliseconds...
 Note that if the webapp is served directly from the
 .war file, configureAndWatch() cannot be used because
 it requires a system file path. In that case, this
 param will be ignored.  Set to 0 or don't specify this
 param to do a normal configure(). --
param-namelog4j-cron/param-name
param-value5000/param-value
/init-param
!-- optional param for use with a File Appender.
 Specifies a path to be read from a log4j xml
 config file as a system property. The property name is
 dynamically generated and takes on the following pattern:
 [webapp name].log.home
 In Barracuda's case, it would be Barracuda.log.home.
 The path defaults to WEB-INF/logs directory, which is created
 if it doesn't exist, unless the webapp is running directly
 from a .war file.
 Note that, if specified, the value is an absolute path, not
 relative to the webapp. --
!-- init-param
param-namelog4j-log-home/param-name
param-value/usr/local/logs/tomcat/param-value
/init-param --
load-on-startup1/load-on-startup
/servlet

And for logging to file, a system variable is automatically created by 
Log4jInit.  The name is different for each webapp and predictable because 
it is based on the context name of the webapp.  For instance,  if I have a 
context with a path of /Barracuda, then in my log4j.xml I use the 
variable ${Barracuda.log.home} to specify my filepath for a file appender 
such as:

appender name=A2 class=org.apache.log4j.FileAppender
param name=File value=${Barracuda.log.home}/main.log /
param name=Append value=false /
layout class=org.apache.log4j.PatternLayout
param name=ConversionPattern value=%-4r [%t] %-5p %c %x - 
%m%n/
/layout
/appender

As you can see above in the configuratin for Log4jInit, there is a param 
you can set called log4-log-home where you can set any 

Re: how many tomcat in a machine?

2002-11-14 Thread Rodrigo Ruiz
It all depends on the workload they must support.

In my single CPU (800MHz / 256Mb / IDE HD), I usually have two or three
Tomcats for development, but
that's because the workload in my machine is very low (only one client, me
:-)

In production, you should test how performance degrades when you add another
Tomcat server. Without benchmarking it's imposible to know the answer to
your question, as it all depends on your applications,
and the use you make of them.

Anyway, a single tomcat instance can be configured to serve multiple web
applications from different ports, or
virtual hosts if you prefer. And it will need less resources than multiple
ones. You could consider it as an option.

Hope it helps

Rodrigo

- Original Message -
From: Jose Antonio Martinez [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Thursday, November 14, 2002 9:49 AM
Subject: how many tomcat in a machine?


 how many tomcat server do you think can i put in a big
 machine like this? :

Memory: 2G
 2*CPU: PIII 1100 Mhz (aprox)
  Disk: scasi raid




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RE: how many tomcat in a machine?

2002-11-14 Thread Turner, John

A key problem to using a single Tomcat instance with multiple web
applications is that a problem with Tomcat or a problem with one single web
app effects all the others.  In a shared server environment (application
service provider, for example) you would be better off having multiple
instances of Tomcat so that you can manage each instance separately without
effecting the others.

John


 -Original Message-
 From: Rodrigo Ruiz [mailto:rruiz;gridsystems.com]
 Sent: Thursday, November 14, 2002 6:43 AM
 To: Tomcat Users List
 Subject: Re: how many tomcat in a machine?
 
 
 It all depends on the workload they must support.
 
 In my single CPU (800MHz / 256Mb / IDE HD), I usually have 
 two or three
 Tomcats for development, but
 that's because the workload in my machine is very low (only 
 one client, me
 :-)
 
 In production, you should test how performance degrades when 
 you add another
 Tomcat server. Without benchmarking it's imposible to know 
 the answer to
 your question, as it all depends on your applications,
 and the use you make of them.
 
 Anyway, a single tomcat instance can be configured to serve 
 multiple web
 applications from different ports, or
 virtual hosts if you prefer. And it will need less resources 
 than multiple
 ones. You could consider it as an option.
 
 Hope it helps
 
 Rodrigo
 
 - Original Message -
 From: Jose Antonio Martinez [EMAIL PROTECTED]
 To: [EMAIL PROTECTED]
 Sent: Thursday, November 14, 2002 9:49 AM
 Subject: how many tomcat in a machine?
 
 
  how many tomcat server do you think can i put in a big
  machine like this? :
 
 Memory: 2G
  2*CPU: PIII 1100 Mhz (aprox)
   Disk: scasi raid
 
 
 
 
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  Yahoo! Messenger
  Nueva versión: Webcam, voz, y mucho más ¡Gratis!
  Descárgalo ya desde http://messenger.yahoo.es
 
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RE: how many tomcat in a machine?

2002-11-14 Thread Turner, John

At least 2 dozen.

John


 -Original Message-
 From: Jose Antonio Martinez [mailto:lfbbes;yahoo.es]
 Sent: Thursday, November 14, 2002 3:49 AM
 To: [EMAIL PROTECTED]
 Subject: how many tomcat in a machine?
 
 
 how many tomcat server do you think can i put in a big
 machine like this? :
 
Memory: 2G
 2*CPU: PIII 1100 Mhz (aprox)
  Disk: scasi raid 
 
 
 
 
 ___
 Yahoo! Messenger
 Nueva versión: Webcam, voz, y mucho más ¡Gratis! 
 Descárgalo ya desde http://messenger.yahoo.es
 
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RE: how many tomcat in a machine?

2002-11-14 Thread Craig R. McClanahan


On Thu, 14 Nov 2002, Turner, John wrote:

 Date: Thu, 14 Nov 2002 08:27:56 -0500
 From: Turner, John [EMAIL PROTECTED]
 Reply-To: Tomcat Users List [EMAIL PROTECTED]
 To: 'Tomcat Users List' [EMAIL PROTECTED]
 Subject: RE: how many tomcat in a machine?


 A key problem to using a single Tomcat instance with multiple web
 applications is that a problem with Tomcat or a problem with one single web
 app effects all the others.  In a shared server environment (application
 service provider, for example) you would be better off having multiple
 instances of Tomcat so that you can manage each instance separately without
 effecting the others.


The other side of the coin is that sharing a single Tomcat instance saves
a ***lot*** of memory, because the system classes are shared.

You can mitigate most, but not all, of the impacts apps can have on each
other by using a security manager that is appropriately configured.  Glenn
Nielsen (a Tomcat developer) has posted quite a few helpful documents to
TOMCAT-USER on how to set this up -- see the mailing list archives for
details.  And, if you're coming to Las Vegas for ApacheCon next week, his
session on how to do this is a must attend for anyone contemplating
setting up this sort of thing.

 John

Craig


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RE: how many tomcat in a machine?

2002-11-14 Thread Turner, John

OK, thanks for the tip. 

John


 -Original Message-
 From: Craig R. McClanahan [mailto:craigmcc;apache.org]
 Sent: Thursday, November 14, 2002 12:13 PM
 To: Tomcat Users List
 Subject: RE: how many tomcat in a machine?
 
 
 
 
 On Thu, 14 Nov 2002, Turner, John wrote:
 
  Date: Thu, 14 Nov 2002 08:27:56 -0500
  From: Turner, John [EMAIL PROTECTED]
  Reply-To: Tomcat Users List [EMAIL PROTECTED]
  To: 'Tomcat Users List' [EMAIL PROTECTED]
  Subject: RE: how many tomcat in a machine?
 
 
  A key problem to using a single Tomcat instance with multiple web
  applications is that a problem with Tomcat or a problem 
 with one single web
  app effects all the others.  In a shared server environment 
 (application
  service provider, for example) you would be better off 
 having multiple
  instances of Tomcat so that you can manage each instance 
 separately without
  effecting the others.
 
 
 The other side of the coin is that sharing a single Tomcat 
 instance saves
 a ***lot*** of memory, because the system classes are shared.
 
 You can mitigate most, but not all, of the impacts apps can 
 have on each
 other by using a security manager that is appropriately 
 configured.  Glenn
 Nielsen (a Tomcat developer) has posted quite a few helpful 
 documents to
 TOMCAT-USER on how to set this up -- see the mailing list archives for
 details.  And, if you're coming to Las Vegas for ApacheCon 
 next week, his
 session on how to do this is a must attend for anyone contemplating
 setting up this sort of thing.
 
  John
 
 Craig
 
 
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