Liferay + Alfresco on OpenVZ

This post is similar to my last entry, as it deals with Java apps and resource settings in OpenVZ. Today I tried to fire up Liferay 5 with the Alfresco 2.1 WAR on Tomcat 5.5, and kept getting the following OutOfMemoryError:

INFO: Starting Coyote HTTP/1.1 on http-8080
Jul 10, 2008 7:50:07 PM org.apache.jk.common.ChannelSocket init
INFO: JK: ajp13 listening on /0.0.0.0:8009
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:295)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:433)
Caused by: java.lang.OutOfMemoryError: unable to create new native thread
at java.lang.Thread.start0(Native Method)
at java.lang.Thread.start(Thread.java:597)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.(ThreadPool.java:648)
at org.apache.tomcat.util.threads.ThreadPool.openThreads(ThreadPool.java:520)
at org.apache.tomcat.util.threads.ThreadPool.start(ThreadPool.java:149)
at org.apache.jk.common.ChannelSocket.init(ChannelSocket.java:436)
at org.apache.jk.server.JkMain.start(JkMain.java:328)
at org.apache.jk.server.JkCoyoteHandler.start(JkCoyoteHandler.java:154)
at org.apache.catalina.connector.Connector.start(Connector.java:1090)
at org.apache.catalina.core.StandardService.start(StandardService.java:457)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:700)
at org.apache.catalina.startup.Catalina.start(Catalina.java:552)
... 6 more

This error turned out to be a bit deceptive and had me needlessly fiddling with Java and OpenVZ memory settings for a time. I should have known to check /proc/user_beancounters right away. If I had, I would have noticed that I was hitting the limit on the numproc parameter, which is set to a very low 240. I increased the limit to to 1000 (just to get an idea of how many processes I would need) using the following command:

vzctl set 101 --save --numproc 1000:1000

Turns out that Liferay with the Alfresco plugin on Tomcat 5.5 using MySQL for everything uses up 248 processes on my machine just to start.

Anyhow, the OutOfMemoryError was due to the process limit and had nothing to do with memory. Just thought I'd share in case anyone else runs into this and Googles before troubleshooting properly.