-Setup with less than 100 nodes
-Things were going fine, and then the whole setup started freezing; initially errors were indicating that we're running out of PerGen space (I upped that to 512m)
-Then same symptoms, setup would freeze; errors were showing running out of heap memory so I increased that 2048 on the master but I can still see the memory increasing significantly (I run GC to avoid the error (clears out more than a G), but I suspect a memory leak somewhere)

-I can't really include a full heap-dump due to some restrictions; however here's a list of the 20 objects retained by size:

Class Name

Retained Size

org.eclipse.jetty.webapp.WebAppClassLoader#1

9,885,754

java.util.Vector#16

9,476,255

java.lang.Object[]#10612

9,476,219

org.apache.commons.jexl.util.introspection.Introspector#1

6,934,833

class org.apache.commons.jexl.util.introspection.UberspectImpl

6,934,833

java.util.HashMap#7545

6,907,893

java.util.HashMap$Entry[]#74405

6,907,825

org.kohsuke.stapler.WebApp#1

6,267,722

java.util.HashMap#4741

6,265,930

java.util.HashMap$Entry[]#72991

6,265,862

class hudson.model.Run

5,730,085

hudson.util.XStream2#4

5,730,037

com.thoughtworks.xstream.core.DefaultConverterLookup#3

5,087,721

com.thoughtworks.xstream.converters.SingleValueConverterWrapper#51

5,050,913

com.thoughtworks.xstream.converters.basic.StringConverter#2

5,050,889

java.util.Collections$SynchronizedMap#39

5,050,861

com.thoughtworks.xstream.core.util.WeakCache#2

5,050,805

java.util.WeakHashMap#389

5,050,765

java.util.WeakHashMap$Entry[]#5781

4,915,608

hudson.model.Hudson#1

3,763,073