"xanderv" wrote : What happens when BOTH the min and max pool sizes are omitted? What does the connection pool use as a default? | | Thanks! | -Xander It is defaulted to 0 and 10 but this configuration is taken from the xslt , it is available in the MetaData object now . Prior Jboss5 the -ds.xml used to get converted to the the xml( containing Mbean's) , this was done using the XSLT transformation. Now you don't use XSLT transformation and all the default values are available in the MetaData code . Go to the jmx-console and verify what values are taken for min/max pool size if you don't define it . View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4153467#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...