
362 Large Scale and Big Data
Figure 11.1 illustrates the relationship between I-SLA and A-SLA in the soft-
ware stack of cloud-hosted applications. In practice, traditional cloud monitoring
technologies (e.g., Amazon CloudWatch*) focus on low-level computing resources
(e.g., CPU speed, CPU utilization, disk speed). In principle, translating the SLAs
of applications’ transactions to the thresholds of utilization for low-level computing
resources is a very challenging task and is usually done in an ad hoc manner due to
the complexity and dynamism inherent in the interaction between the different tiers
and components of the system. In particular, ...