There's another chapter to the story. I noticed recently that NewCompressingMarshallerTestCase, which runs in about half a minute on my Windows laptop, takes about 13 minutes on one of the Red Hat linux test machines. It turns out that the GZipOutputStream constructor takes an order of magnitude longer in linux than in Windows. I've changed CompressingMarshaller so that it reuses a single GZipOutputStream but replaces the Deflater with each call to write(). CompressingUnMarshaller has the symmetric changes with respect to Inflater. Now NewCompressingMarshallerTestCase takes about 18 seconds on my Fedora laptop. I've attached to JBREM-1077 "Fix problem in CompressingMarshaller" a copy of jboss-remoting.jar from the 2.x branch with the changes. View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4248222#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...