Tomcat performance tuning

[rujin raj <ru...@gmail.com>]

Support,


I Installed tomcat 5.5.20 version in my Windows 2008 server and the java
version is Java 1.6.0.b105.We are using  2 Mbps Bandwidth Leased line.In
tomcat we hosted around 5(five) application.When the no of seesion increases
more than 1600 session the total application is slow and not able to open
the application sometime.

1) How can I tune this application in server side for better performance in
tomcat side as well as java?
2) I noticed that the current thread busy count is less but the number
session is more.What might be the problem?
3)More over for a IP more sessions are opened(noticed via Lambda probe).Is
there any problem in that?
4)What is mean by serilizable? For my application it is showing as "No"
5)What is mean by a)Max Threads b)Min and Max spare threads c)current thread
count and current thread busy?

Please help me


Regards
Rujinraj.
System Administrator

Re: Tomcat performance tuning

[Ognjen Blagojevic <og...@gmail.com>]

Rujin,

> I Installed tomcat 5.5.20 version in my Windows 2008 server and the java
> version is Java 1.6.0.b105.We are using  2 Mbps Bandwidth Leased line.In
> tomcat we hosted around 5(five) application.When the no of seesion increases
> more than 1600 session the total application is slow and not able to open
> the application sometime.

In order to solve your problem, you must first determine what is the 
bottleneck of your system. Is it a) network, b) RAM, c) CPU, or d) hard 
disk? Use appropriate tools to figure that out first.

I must notice that 1600 sessions is quite a large number for 2mbps link. 
Do you invalidate sessions and do you have a session timeout setting?

Some frameworks, like JSF implementations, might introduce extensive 
session creation if not used properly. Please explain when is your 
session created and when is destroyed.


> 1) How can I tune this application in server side for better performance in
> tomcat side as well as java?

That depends on the reason for slow down. Most of the time it is not JVM 
or Tomcat's fault, but faulty webapp.

For start, I would recommend to analyze JVM memory consumption, memory 
dump, session content, and to tweak with -Xmx and -Xms parameters, if 
you didn't already do that.

Also watch for garbage collection, how often it happens and when.


> 2) I noticed that the current thread busy count is less but the number
> session is more.What might be the problem?

Those two are not directly related. Active busy thread count is related 
to the number of *simultaneous* requests, while active sessions might 
not issue requests at all (just waiting to be invalidated upon timeout).


> 3)More over for a IP more sessions are opened(noticed via Lambda probe).Is
> there any problem in that?

Sorry, I don't understand this question.


> 4)What is mean by serilizable? For my application it is showing as "No"

That means that Tomcat will be able to persist your sessions to hard 
disk in case of shutdown, and to reload them upon start up. Which means 
that if your sessions are serializable, you will be able to keep them 
across Tomcat restarts, while if they are not, they will be lost.


> 5)What is mean by a)Max Threads b)Min and Max spare threads c)current thread
> count and current thread busy?

a. Maximum number of threads Tomcat will create to answer your clients 
request. That should be over of predicted maximum number of simultaneous 
requests (not sessions!).

b. Minimum and maximum of threads that are currently not answering any 
requests. Minimum will ensure that there is available thread when new 
request comes, and maximum will ensure that JVM does not keep too many 
threads doing nothing and eating up resources.

c1. Current number of active threads processing requests, or waiting to 
process requests.

c2. Current number of active threads processing requests.


They relate like this:

thread_busy <= thread_busy + spare_min <= thread_active <= thread_busy + 
spare_max <= max_threads


-Ognjen

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