QMON: QoS- and Utility-Aware Monitoring in Enterprise Systems

The scale, reliability and cost requirements of enterprise data centers require automation of center management. Examples include provisioning, scheduling, capacity planning, logging and auditing. A key component of such automation functions is online monitoring. In contrast to monitoring systems designed for human users, a particular concern for online enterprise monitoring is Quality of Service (QoS). Since breaking service level agreements (SLAs) has direct financial and legal implications, enterprise monitoring must be conducted so as to maintain SLAs. This includes the ability to differentiate the QoS of monitoring itself for different classes of users or more generally, for software components subject to different SLAs. Thus, without embedding notions of QoS into the monitoring systems used in next generation data centers, it will not be possible to accomplish the desired automation of their operation. This paper both demonstrates the importance of QoS in monitoring and it presents a QoS-capable monitoring system, termed QMON. QMON supports utility-aware monitoring while also able to differentiate between different classes of monitoring, corresponding to classes of SLAs. The implementation of QMON offers high levels of predictability for service delivery (i.e., predictable performance) and it is dynamically configurable to deal with changes in enterprise needs or variations in services and applications. We demonstrate the importance of QoS in monitoring and the QoS capabilities of QMON in a series of case studies and experiments, using a multi-tier web service benchmark.