{"title":"Towards Byzantine Resilient Directories","authors":"Ali Shoker, J. Bahsoun","doi":"10.1109/NCA.2012.14","DOIUrl":"https://doi.org/10.1109/NCA.2012.14","url":null,"abstract":"Notable Byzantine Fault Tolerant protocols have been designed so far. These protocols are often evaluated on simple benchmarks, and few times on NFS systems. On the contrary, studies that addressed the behavior of BFT on large back-ends, like Directories, are few. We believe that studying such systems is crucial for practice community due to their popularity. In this paper, we integrate BFT with OpenLDAP Directory. We introduce the design of the integrated system, that we call BFT-LDAP. Then, we study its behavior accompanied with some useful observations. In addition, we discuss the cost overhead of this integration. Our approach ensures that OpenLDAP legacy code remains completely intact, and that the integration with BFT is straightforward using APIs. Moreover, we convey that the additional performance cost of BFT-LDAP is negligible as compared to that of stand-alone OpenLDAP. We conducted our experiments on Emulab. The experiments indicate that the performance discrepancy of BFT-LDAP is negligible whenever different state-of-the-art BFT protocols are used. Other experiments demonstrate that a little sacrifice in throughput (less than 10%) is needed in order to leverage the resiliency of OpenLDAP against Byzantine faults (i.e., through applying BFT).","PeriodicalId":242424,"journal":{"name":"2012 IEEE 11th International Symposium on Network Computing and Applications","volume":"163 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116400960","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An Online Power Metering Model for Cloud Environment","authors":"Yanfei Li, Y. Wang, Bo Yin, Lu Guan","doi":"10.1109/NCA.2012.10","DOIUrl":"https://doi.org/10.1109/NCA.2012.10","url":null,"abstract":"Energy consumption has become major operational cost in data centers. Virtualization technology used in cloud computing platforms can improve energy efficiency and reduce costs. There are many ongoing research projects focusing on power management for virtualized cloud by making power-aware resource allocation and scheduling policies. However, there is a lack of VM power profiling method in such research, because the power consumption of an individual virtual machine (VM) cannot be measured directly by hardware power meter. In this paper, a novel power metering model is proposed for VMs in the cloud environment, based on online monitoring of system resource metrics, to estimate the power consumption of a physical server as well as one or more VMs running on it. By analyzing problems found in experiments, the model is improved to be the classified-piecewise ternary linear regression model which can achieve higher accuracy. In addition, the model is proved to be effective by running a variety of sample programs. The implementation of our model shows that it can achieve average estimation accuracy of more than 96% with low runtime overhead.","PeriodicalId":242424,"journal":{"name":"2012 IEEE 11th International Symposium on Network Computing and Applications","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131793514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}