Evaluation and design of highly reliable and highly utilized cloud computing systems

Abstract

Cloud computing paradigm has ushered in the need to provide resources to users in a scalable, flexible, and transparent fashion much like any other utility. This has led to a need for developing evaluation techniques that can provide quantitative measures of reliability of a cloud computing system (CCS) for efficient planning and expansion. This paper presents a new, scalable algorithm based on non-sequential Monte Carlo Simulation (MCS) to evaluate large scale cloud computing system (CCS) reliability, and it develops appropriate performance measures. Also, a new iterative algorithm is proposed and developed that leverages the MCS method for the design of highly reliable and highly utilized CCSs. The combination of these two algorithms allows CCSs to be evaluated by providers and users alike, providing a new method for estimating the parameters of service level agreements (SLAs) and designing CCSs to match those contractual requirements posed in SLAs. Results demonstrate that the proposed methods are effective and applicable to systems at a large scale. Multiple insights are also provided into the nature of CCS reliability and CCS design.

The Use of Teleradiology in Turkey: Current Situation and Attitudes of Radiologists

“…In addition, some legal issues, mainly regarding liability, and issues related to patient privacy and patient safety, as yet remain unsolved. 7,[15][16][17] On the other hand, the major problems in Turkish models are similar to those in European models. Primary-reading teleradiology in Turkey have many serious problems such as unregistered, unlicensed, lowquality ghost reporting.…”

Reliability and high availability in cloud computing environments: a reference roadmap

“…Snyder et al [48] presented an algorithm for evaluating the reliability and performance of cloud computing datacenters. In this study, a non-sequential Monte Carlo simulation was used to analyze the system reliability.…”

“…Therefore it can be said that about 80% of cloud system failures are related to storage failures. Some researches conducted about the networks of CCS show that most of the datacenter networks and switches are highly reliable and only load balancers most often experience faults due to software failures [26,70].…”

“…Although many research papers and studies have been conducted in recent years such as studies in [26,[29][30][31][32][33][34], but each of these previous works focused on a special aspect of HA in cloud computing and there are no comprehensive studies, which cover all aspects of HA problem in cloud computing environment based on all cloud actors' requirements. In this paper, a comprehensive study results about cloud computing reliability and HA problems as a 'Reference Roadmap' for future researchers will be proposed.…”

“…However, the lack of reliability and high availability of cloud services is quickly becoming a major issue [25,26]. Research reports express that about $285 million have been lost yearly due to cloud service failures and offering availability of about 99.91% [26].…”