Hello all,
I'm currently working on upgrading our systems from using Tomcat 5.0.27 to
6.0.14.
The upgrades are not being done in place (ie, we will have both systems out
there, and will be doing migrations to the new version). I have been able to
resolve most of the issues we have run into thus far, however, I am now
somewhat stuck, and am hoping someone here may be able to help.
About the environment:
Shared hosting, with approximately 300-600 users on a server, with an average
of ~1500 applications (many users have a few applications). Not all users are
utilizing any java at all, however. Apache 1.3.33 is running and configured to
serve static content.
The older servers with TC5 on them have ~6GB of available RAM, new servers for
TC6 have 8GB of RAM.
Customer content is stored on a remote NAS server.
While I understand that having the <Host> and <Context> declaration for all
users listed in server.xml, that is how we have it currently configured.
About the problem:
When tomcat is started and running on our existing 5.0.27 server, it uses
approximately 1GB of RAM, and successfully runs all applications without issue.
When starting tomcat on the 6.0.14 server with the _exact_ same content,
however, it runs out of heap space. This is the issue I'm running into right
now that I can't seem to find any answers about. Attempting to increase the
available heap results in an error allocating memory upon startup.
The output from jmap seems to show that the majority of the heap/memory is
being consumed by character arrays.
When viewing the {tomcat.home}/work/{engine}/{application} directory, it
appears there is a fair difference on how these are loaded into tomcat.
On Tomcat5, this directory consists of only directories that contain a WEB-INF
directory in them, and each of those have a tldCache.ser file.
On Tomcat6, this directory consists of all directories located inside a
directory that contains a WEB-INF directory.
For example:
Tomcat 6:
[EMAIL PROTECTED] ]# pwd ; find .
/web/tomcat/work/hosting/sitename.com
.
./_
./cgi
./stats
./php_uploads
./images
./ad
./Video
./Templates
./Flv
./Songs
./newwebsite
./old files
./manager
Tomcat5:
[EMAIL PROTECTED] ]# pwd; find .
/web/tomcat/work/hosting/sitename.com
.
./_
./_/tldCache.ser
And the contents of the actual home directory are:
[EMAIL PROTECTED] html]# find . -maxdepth 1 -type d
.
./cgi
./stats
./php_uploads
./WEB-INF
./images
./ad
./Video
./Templates
./Flv
./Songs
./newwebsite
./old files
I have read http://wiki.apache.org/tomcat/FAQ/Memory and attempted all the
suggestions there, to no avail.
Thus, it appears that on Tomcat6, it is attempting to load all of these paths
into memory, and eventually runs out. Tomcat5 did not load all of the paths to
directories without applications, and thus uses less of the heap.
Does it seem like I am on the right track here? Have others encountered this
in the past? Is there a way to prevent this behavior within Tomcat 6?
I thank you for any insight you can provide on this issue.
Sincerely,
Dan D.
