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From Shanti Suresh <>
Subject Tomcat inconsistency across two servers - any thoughts?
Date Wed, 25 Jan 2012 21:19:32 GMT

We have two RedHat Linux servers, Dlv1 and Dlv2, running:
Linux 2.6.18-274.3.1.el5 #1 SMP Fri Aug 26 18:49:02 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux

Each has an identical 7.0.23 Tomcat engine running, front-ended by Apache/2.2.3.  Each Tomcat
runs exact binary-compatible applications.  (Dlv2 is running Dlv1's image.)

Dlv2 is leaking heap memory and is consistently slower.   A heapdump analysis of Dlv2 shows
finalizers queuing up on Dlv2 pointing to a possible backlog into the backend database.  Threads,
monitors etc. look healthy on Dlv2.  Dlv2 is out of the load-balancer pool, needless to say.
 Database queries directly from Dlv1 and Dlv2 show no differences.

What else could cause JVM runtime performance differences?

An md5sum comparison of the "/usr/lib/jvm/java-1.6.0-sun-" installation on
Dlv1 and Dlv2 show differences in several files.  But these seem to be a repeatable difference
almost like a watermark, a signature or the IP address encoded for a machine-specific difference.

I was going to tar up Dlv1's Java1.6 install and untar it on DLv2.  But I notice md5sum differences
in the older JDK1.5 installs as well.  Are these md5 checksum differences common across RPM
installs of Java?

Do you have any tips on other causes that might impact a JVM's runtime operation?

Any suggestions on what else I might try?  


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