Performance issues with 7.4.0 Cluster

Problem:
After ~10 days of constant load (per day ~20mio messages) the producer-throughput of the HA cluster is decreased to 150-200 messages per second which is much less than the regular load. We have recognized that the cpu load of the Node2 (passive) VM is at 20% (see node2_cpu_slow.png) and the allocated memory is at 2GB (see node2_vm_slow.png). After a restart of the Standby SMQ on Node2 we see a initial load of 4-5% even if we load the queue with ~800 messages per second. In progress.xls  progress.xls  you can see the average throuput right before the restart and right after the restart.

Setup/Background:
Our regular throughput is at 400 messages per second. We have one single-threaded producer which could load a clean HA-SMQ at ~1.400 messages per second. The consumer service is a multi-threaded spring-application which uses the springsupport.jar. We use a Active-Standby file-replicated 7.4.0 HA-cluster of two similar nodes with a Quadcore XEON X5450 @3,00GHz / 4GB RAM and a 256MB Raid-Controller with two 146GB SAS-Disks. The SMQ-store is on a Ext2 filesystem. Both nodes are connected with a crossover network cabel on a 1Gbit fullduplex interface. Both VM’s can access up to 2,5GB memory. (Node1 = Active SMQ and Node2 = Standby SMQ)


Thanks for your help,
Michael


Some JVM Screenshots:

Fast processing - CPU Passive Standby


Fast processing - VM Passive Standby


Slow processing - CPU Passive Standby


Slow processing - VM Passive Standby