Tomcat crash... connection_pool_size ?

Posted on 2011-10-15
Last Modified: 2013-12-02
We run j2e under iis / tomcat.
One of our server suddently crashes every hours or so. It does not seem to be related to server load as it can crash 3 times at 2H00 in the morning and behave ok several hours in the afternoon.
However, we looked at the logs and saw the message :
your connection_pool_size is probably less than the threads in your web server!
So is setting a higher number (I think 250 is default) can solve the problem ?
Thanks for help... URGENT
Question by:javilmer
    LVL 9

    Accepted Solution

    250 should be more than enough and the randomness of the crashes confirm this.
    As the crashes are random try to find out  if you don't have a spider or other batch request process going on or a security software (nessus) running

    Another option is to upgrade IIS

    A bientot

    Read the following document  ( search for connection_pool_size)

    ---- snip

    This defines the number of connections made to the AJP backend that are maintained as a connection pool. It will limit the number of those connection that each web server child process can made.
    Connection pool size property is only used for multi threaded web servers such as Apache, IIS and Netscape/Sun. The connection_pool_size property needs to reflect the number of requests one web server process should be able to send to a backend in parallel. Usually this is the same as the number of threads per web server process. JK will discover this number for the Apache web server automatically and set the pool size to this value. For IIS the default value is 250 (before version 1.2.20: 10), for Netscape/Sun the default value is 1.

    We strongly recommend adjusting this value for IIS and the Netscape/Sun to the number of requests one web server process should be able to send to a backend in parallel. You should measure how many connections you need during peak activity without performance problems, and then add some percentage depending on your growth rate. Finally you should check, whether your web server processes are able to use at least as many threads, as you configured as the pool size.
    LVL 9

    Expert Comment

    oups sorry.... previous message send while working on it

    First of all, are you sure the crashes are related to the error message ?
    Is the error message present on logs on non crash times ?

    Is the problem limited to a single server ? Could be a HW problem (memory?)

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