Navia Marlon, Campelo José Carlos, Bonastre Alberto, Ors Rafael
ITACA, Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, España.
Carrera de Computación, Escuela Superior Politécnica Agropecuaria de Manabí (ESPAM MFL), 10 de Agosto and Granda Centeno Street, No. 82, 130601 Calceta, Manabí, Ecuador.
Sensors (Basel). 2017 Dec 23;18(1):28. doi: 10.3390/s18010028.
Monitoring is one of the best ways to evaluate the behavior of computer systems. When the monitored system is a distributed system-such as a wireless sensor network (WSN)-the monitoring operation must also be distributed, providing a distributed trace for further analysis. The temporal sequence of occurrence of the events registered by the distributed monitoring platform (DMP) must be correctly established to provide cause-effect relationships between them, so the logs obtained in different monitor nodes must be synchronized. Many of synchronization mechanisms applied to DMPs consist in adjusting the internal clocks of the nodes to the same value as a reference time. However, these mechanisms can create an incoherent event sequence. This article presents a new method to achieve global synchronization of the traces obtained in a DMP. It is based on periodic synchronization signals that are received by the monitor nodes and logged along with the recorded events. This mechanism processes all traces and generates a global post-synchronized trace by scaling all times registered proportionally according with the synchronization signals. It is intended to be a simple but efficient offline mechanism. Its application in a WSN-DMP demonstrates that it guarantees a correct ordering of the events, avoiding the aforementioned issues.
监控是评估计算机系统行为的最佳方法之一。当被监控系统是分布式系统时，例如无线传感器网络（WSN），监控操作也必须是分布式的，以提供分布式跟踪以供进一步分析。必须正确建立分布式监控平台（DMP）记录的事件发生的时间顺序，以提供它们之间的因果关系，因此在不同监控节点中获取的日志必须进行同步。应用于DMP的许多同步机制包括将节点的内部时钟调整到与参考时间相同的值。然而，这些机制可能会创建一个不连贯的事件序列。本文提出了一种新方法，以实现DMP中获取的跟踪的全局同步。它基于监控节点接收的周期性同步信号，并与记录的事件一起记录。该机制处理所有跟踪，并通过根据同步信号按比例缩放所有记录的时间来生成全局后同步跟踪。它旨在成为一种简单但高效的离线机制。其在WSN-DMP中的应用表明，它保证了事件的正确排序，避免了上述问题。
