Performance and Availability Evaluation of Software Systems

在当今世界，软件系统的性能和可用性是影响收入的两个关键因素。软件性能不佳或停机一小时可能会给企业带来巨大的经济损失。*软件应用程序越来越多地部署在云中，因为云计算提供了几个优势。例如，它使应用服务提供商不必购买和维护数据中心，从而降低了运营成本；它允许根据需要按使用付费动态扩展计算资源；它以最低的成本促进了在多个地理位置的轻松部署。此外，在移动领域，云计算可以帮助将密集的计算从资源受限的移动设备转移到资源丰富的云上，从而降低电池功耗。*虽然云计算的目标一直是降低计算成本，但遗憾的是，这一概念受到了性能和可用性问题的打击。例子比比皆是：微软Azure的频繁停机就是其中之一。Rackspace的云服务降级是另一个原因。因此，软件供应商有责任确保其软件在出现此类问题时满足性能和可用性要求。实现这一点的一种方法是利用多个云。然而，在多云环境中管理应用程序是一项昂贵而复杂的任务，因此需要有效的策略。*拟议研究的目标是开发新的建模技术、工具和算法，以帮助评估使用多云的软件系统的性能(响应时间或吞吐量)和可用性。这些技术和工具将帮助软件提供商提前规划并以具有成本效益的方式管理计算资源。*建议包括(I)开发和验证新型模型以评估云中应用程序的性能和可用性；(Ii)开发工具帮助建模过程；(Iii)在多云环境中优化应用程序的部署和配置，以最大限度地降低成本，并满足其性能和可用性要求；(Iv)计算分流移动应用程序，以提高其性能和降低移动设备的电池功耗。*这项研究的成果如果成功，将有助于提高软件系统的质量和降低业务成本。加拿大的这些发展可以帮助从战略上定位这里的软件业，并帮助推动它在全球范围内的发展。**

In today's world, performance and availability of software systems are two critical revenue impacting factors. Poor performance of software or an hour of its downtime can result in significant financial loss to businesses.****Increasingly, software applications are being deployed in clouds because cloud computing offers several advantages. For example, it relieves the application service providers from buying and maintaining data centers thereby reducing the operational costs; it allows dynamic scaling of computational resources as required on a pay-per-use basis; and, it promotes easy deployment in multiple geographic locations at minimal cost. Moreover, in mobile domain, cloud computing can facilitate offloading of intensive computations from resource-constrained mobile devices to resource-rich cloud, thereby reducing battery power consumption.****Although the aim of cloud computing has been to reduce computational cost, unfortunately the concept has been hit by performance and availability issues. Examples abound: Frequent outages of Microsoft's Azure is one. Rackspace's cloud service degradation is another. The onus is therefore on the software providers to ensure that their softwares meet the performance and availability requirements in presence of such issues. One way to achieve this could be through utilizing multiple clouds. However, managing applications in multi-cloud environment is a costly and complex task and hence calls for efficient strategies.****The goal of the proposed research is to develop novel modeling techniques, tools and algorithms that would help in evaluating performance (response time or throughput) and availability of software systems utilizing multiple clouds. Such techniques and tools will assist the software providers to plan in advance and manage the computational resources in a cost-effective manner.****The proposal includes (i) development and verification of novel models to evaluate performance and availability of applications in clouds; (ii) development of tools to aid in the modeling process; (iii) optimal deployment and provisioning of applications in multi-cloud environment that would minimize cost, and would meet their performance and availability requirements; (iv) computation offloading of mobile apps to improve their performance and reduce the battery power consumption of the mobile device. ***The outcome of this research effort, if successful, will help improve the quality of software systems and reduce business cost. Such developments in Canada can help strategically position the software industry here and help advance it globally.**