I. Introduction
Cloud monitoring and log management is important for effective cloud resources orchestration. Real time decision is taken based on the current and old historical system statistics values. Reading logs from cloud logs generator (data sources) is critical to get refreshed and accurate log values. In [1] a Xen hypervisor data sources is studied to get the most accurate with a lower cost log data source for low level logging of Virtual Machine (VM) CPU usage. In [2] a new log-tracing tool is proposed that track logs data sources in a smooth way for KVM hypervisor, which can reduce the logs gathering overhead latency. However for both work, logs must be captured (sampled every periodic time interval) and send to cloud manager. Logs must be captured and filtered or aggregated based on the need of the cloud management system. Cloud manager uses current log values and old traces (historical logs) mainly to make actions on the fly. Cloud manager need to communicate with monitoring tool to get data, ether by pulling the requesting data from monitoring tool or by the monitoring tool continually pushing logs to it. Logging process causes transmission cost over the network and processing cost in cloud management system.