You might want to check to make sure you have enough tomcat threads for
each apache thread.
I usually give tomcat a few more threads than apache just to make sure I
do not run out.
-------snip----------------
<!-- Define a Coyote/JK2 AJP 1.3 Connector on port 8009 -->
<Connector port="8009"
enableLookups="false" redirectPort="8443" debug="0"
minSpareThreads="100" maxSpareThreads="300"
protocol="AJP/1.3" />
-------snip----------------
So you might want to increase min and max spare threads to accomodate
more requestes from apache to tomcat via mod_jk.
Randall
-----Original Message-----
From: Shawn Wilson [mailto:[EMAIL PROTECTED]
Sent: Wednesday, May 05, 2004 9:50 AM
To: [EMAIL PROTECTED]
Subject: mod_jk hangs
Just yesterday we started running into problems requesting pages on our
production website through mod_jk. Previously everything had been
working fine for months. Essentially what happens is when you request
the page for the first time (doesn't seem to matter what browser you're
using) the browser just sits and spins. Then after hitting refresh
(Ctrl+R) a couple times it finally comes up. Subsequent visits to the
same page continue to work for me in Mozilla but after closing IE and
reopening it after a couple more requests it hangs again. In case it
helps, the site in question is http://www.atmreports.com.
I simply cannot figure out what is going on. I do see many errors in the
mod_jk.log, but these had been there before when everything worked fine
too:
[Wed May 05 09:27:46 2004] [jk_ajp_common.c (1137)]: Error reading
reply from tomcat. Tomcat is down or network problems.
[Wed May 05 09:27:46 2004] [jk_ajp_common.c (1290)]: ERROR: Receiving
from tomcat failed, recoverable operation. err=0
[Wed May 05 09:27:46 2004] [jk_ajp_common.c (1309)]: sending request to
tomcat failed in send loop. err=0
[Wed May 05 09:27:46 2004] [jk_ajp_common.c (738)]: ERROR: can't
receive the response message from tomcat, network problems or tomcat is
down. err=-1
A few things to note, any of which may contribute to the problem but for
the life of me I can't figure out how:
1. On Friday we just moved out datacenter to a new location. However we
see this problem even internally at the location so I don't believe it
is any sort of routing issue (and the problem didn't start until
Tuesday).
2. The clock on this webserver was many hours off. On Tuesday (yes, the
day the problems started) the clock was synchronized and the timezone
correctly set so the machine now has correct time. This seems to be the
most probable cause simply because it happened around the same time, but
I just can't understand why or how.
3. Yesterday we rebooted the box to see if that would help. It did. We
didn't have any more problems at all that day until this morning we see
the problems again. Today we recycled just tomcat and that seems to have
fixed it as well, though I expect that by tomorrow I will see the
problem again.
4. I wouldn't think this could have anything to do with that new Sasser
worm, but listing that just in case.
The machine is running Linux kernel 2.4.20-8 with httpd-2.0.40-21 and
jakarta-tomcat-5.0.18. We are running 4 instances of tomcat on the box,
each started with the following JVM options:
-Xmn128M -Xmx1024M -Djava.awt.headless=true
Nothing having to do with configuration has changed at all in a long
time. Here is the relevant configuration sections:
# Mod_jk (Tomcat connector)
LoadModule jk_module modules/mod_jk.so
<IfModule mod_jk.c>
JkWorkersFile /etc/httpd/conf/workers.properties
JkLogFile /var/log/httpd/mod_jk.log
JkLogLevel info
JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
JkOptions +ForwardKeySize +ForwardURICompat -ForwardDirectories
JkRequestLogFormat "%w %V %T"
</IfModule>
...and later (in a <VirtualHost> section)...
JKMount /myreports balancer
JKMount /myreports/* balancer
Here is our workers.properties file (comments removed):
workers.java_home=/usr/java/j2sdk1.4.2_03
ps=/
worker.list=balancer
worker.ajp13_0.port=8090
worker.ajp13_0.host=localhost
worker.ajp13_0.type=ajp13
worker.ajp13_0.lbfactor=1
worker.ajp13_1.port=8091
worker.ajp13_1.host=localhost
worker.ajp13_1.type=ajp13
worker.ajp13_1.lbfactor=1
worker.ajp13_2.port=8092
worker.ajp13_2.host=localhost
worker.ajp13_2.type=ajp13
worker.ajp13_2.lbfactor=1
worker.ajp13_3.port=8093
worker.ajp13_3.host=localhost
worker.ajp13_3.type=ajp13
worker.ajp13_3.lbfactor=1
worker.balancer.type=lb
worker.balancer.balanced_workers=ajp13_0, ajp13_1, ajp13_2, ajp13_3
worker.balancer.sticky_session=1
Any help would be greatly appreciated!
Thanks,
-shawn
--
====================================
Shawn Wilson [EMAIL PROTECTED]
Software Developer, ATMReports.com
PH: 877-327-0873, FAX: 406-294-5806
====================================
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