An adaptive dynamic domain algorithm has been proposed to solve the issue that the fixed domain can not adapt to the variation of the cluster scale. By computing the intrusive load obtained by the monitoring system

the algorithm can control the numbers and the sizes of monitoring domains in an acceptable level according to the intrusion tolerance degree. The fixed domain monitoring node is not efficient as its load is high. A floating domain monitoring node method has been proposed to re-select the domain monitoring node and automatically update the roles of the nodes when the load of the node is high. To reduce the overhead incurred by monitoring system and improve the response time of executing monitoring tasks

an adaptive thread pool and a database connection pool have been designed. The measurements on monitoring CPU usage show that the response time of monitoring one node is 128ms

and that of monitoring 20 nodes is 242ms. A comparative performance measurement has been performed between the solutions with an adaptive database connection pool and that without a pool. The results show that the average intrusion on CPU usage in 300 seconds is 1.80% with a pool and 7.53% without a pool

and the numbers of completed tasks are 12 364 and 2 769

respectively.