This problem is already related in JIRA (https://jira.jboss.org/jira/browse/JBTM-444) . Our production server reachs UserLoad value of 100% in 3 our 4 days, and the only solution is to stop and restart the server.
We intensively use JMS queue (JBOSS MQ and Oracle for persistence) and MDB which use XA transactions.

What is the actual workaround for this problem ?
Is the problem still in the Jboss 5 server ?
Is the problem the surce of following logs ? :

log:
2009-05-04 00:07:04,640 DEBUG [com.arjuna.ats.txoj.logging.txojLoggerI18N] [com.arjuna.ats.internal.txoj.recovery.TORecoveryModule_3] - TORecoveryModule - first pass
2009-05-04 00:07:04,640 DEBUG [com.arjuna.ats.jta.logging.loggerI18N] [com.arjuna.ats.internal.jta.recovery.info.firstpass] Local XARecoveryModule - first pass
2009-05-04 00:07:14,642 DEBUG [com.arjuna.ats.arjuna.logging.arjLogger] Periodic recovery - second pass <lun., 4 mai 2009 00:07:14>