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From André Warnier>
Subject Re: Tomcat stops responding
Date Fri, 17 Dec 2010 13:59:49 GMT
K J.Sreekumar wrote:
> Hello All,
> We are hitting on a weird problem with tomcat 6 production server (which is
> a serious concern for us now). Hoping to get help from the you guys
> This is the problem -
>    1. Our tomcat 6 server (version 6.0.29) does not respond after working
>    for a couple of days. Browsers are unable to find application URLs (which
>    were previously processed normally).
>    2. The logs does not show any error.
>    3. There are only a total of 50-60 threads in the thread dump, mostly in
>    WAIT state. Also, it does not show any BLOCKING or LOCKED threads.
>    4. Memory utilization was 400MB only
>    5. TOMCAT restart does not fix the problem. The machine needs to be
>    restarted to resume normal operation.
>    6. Netstat did not reveal any extraneous connections
> We are running Tomcat 6.0.29 on the following platform -
> OS: Windows server 2003 R2 Enterprise Edition SP2
> Hardware: Intel Xeon L5520 2.27 GHz (16 CPU threads )
The fact that restarting Tomcat does not help, and that there is no error in the logs, 
raises a strong suspicion that the problem may be external to Tomcat.
So, just to eliminate certain side-issues :

1) what do you mean by :
 >    1. ... Browsers are unable to find application URLs (which
 >    were previously processed normally).

What error do you get in the browser ? (Preferably, use a browser other than IE, or if you

do use IE, then in the options disable the "friendly error messages")

2) When the problem happens again :

- does the host still respond to "ping" ?

- on the server, in a command window, do : netstat -p tcp -anb
   and paste the complete result here

- from another workstation :
   - open a command window
   - enter : telnet (hostname) (port)     (the port on which Tomcat listens, presumabyl 80)
     you will not get a prompt, you will get a blank screen.
   - now you have to type blind, because you will not get an echo :
     GET / HTTP/1.1
     (meaning 2 times "return"

   what do you see ?

- do the same from a command window on the server itself, using "localhost" as the 
hostname.  Same result ?

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