Reliability and Availability Evaluation for Cloud Data Center Networks Using Hierarchical Models

Abstract

Modeling a cloud computing center is crucial to evaluate and predict its inner connectivity reliability and availability. Many previous studies on system availability/reliability assessment of virtualized systems consisting of singular servers in cloud data centers have been reported. In this paper, we propose a hierarchical modeling framework for the reliability and availability evaluation of tree-based data center networks. The hierarchical model consists of three layers, including 1) reliability graphs in the top layer to model the system network topology; 2) a fault-tree to model the architecture of the subsystems; and 3) stochastic reward nets to capture the behaviors and dependency of the components in the subsystems in detail. Two representative data center networks based on three-tier and fat-tree topologies are modeled and analyzed in a comprehensive manner. We specifically consider a number of case-studies to investigate the impact of networking and management on cloud computing centers. Furthermore, we perform various detailed analyses with regard to reliability and availability measures for the system models. The analysis results show that appropriate networking to optimize the distribution of nodes within the data center networks can enhance the reliability/availability. The conclusion of this paper can be used toward the practical management and the construction of cloud computing centers. INDEX TERMS Data center network (DCN), reliability, availability, hierarchical modeling, reliability graph (RG), fault tree (FT), stochastic reward net (SRN).

A Hierarchical Modeling and Analysis Framework for Availability and Security Quantification of IoT Infrastructures

“…The proposed hierarchical models of the IoT smart factory infrastructure are all implemented in symbolic hierarchical automated reliability and performance evaluator (SHARPE) [58,59]. The input parameters are mostly based on previous experimental studies and consolidated works [19,27,[60][61][62] as shown (i) in Table 1 for default input parameters used in software/hardware sub-models of cloud member system, (ii) in Table 2 for default input parameters of software/hardware sub-models of fog member system, and (iii) in Table 3 for default input parameters of edge member system's software/hardware sub-models. The developed hierarchical model of the IoT smart factory infrastructure is analyzed in regard to various analysis outputs including (i) SSA, (ii) sensitivity of SSA wrt.…”

“…Hierarchical models in practice are often developed in modeling and analysis of sophisticated and large-sized systems and/or multi-fold system of systems in order to reduce largeness of monolithic models and to prevent model computation and analysis processes from state-space explosion problems [18,19]. A hierarchical system model often consists of multi-level models in which (i) the upper levels are composed of non-state-space model types including FT or RBD, especially, for structured modeling of systems/subsystems, or reliability graph (RG) for network modeling [20], and (ii) the lower levels consists of state-space models (e.g., CTMC or SPN, etc.)…”

A Model for Availability and Security Risk Evaluation for Systems With VMM Rejuvenation Enabled by VM Migration Scheduling

“…Nguyen et al [28], [29] provide a comprehensive dependability modeling of virtualized data centers. Their work covers the reliability and availability of different scenarios and virtualized architectures.…”

Spectral Expansion Method for Cloud Reliability Analysis

“…For a small range of N(Y), Cases 2 and 3 show improving result better than Case 1, whereas for large M(Y), Case 1 shows better results. e possible explanation for this is that (i) the processor availability reduces when both failure and repair rates increase, (ii) optimal value of M is larger for Case 1 than for Cases 2 and 3. e proposed reliability modelling using SPM is compared with other standard reliability models such as reliability graph model [36] and hierarchical correlation model (HCM) [11]. ese two models evaluate reliability in the cloud-based system.…”