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。软件性能不佳或一小时的停机时间可能会给企业造成重大经济损失。*越来越多的软件应用程序被部署在云中，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;它允许在按使用付费的基础上根据需要动态扩展计算资源;并且，它促进了以最低成本在多个地理位置的轻松部署。此外，在移动的领域，云计算可以促进将密集计算从资源受限的移动的设备卸载到资源丰富的云，从而降低电池功耗。*虽然云计算的目标是降低计算成本，但不幸的是，这个概念受到了性能和可用性问题的影响。例子比比皆是：微软Azure的频繁中断就是其中之一。Rackspace的云服务降级是另一个问题。因此，软件供应商有责任确保其软件在出现这些问题时符合性能和可用性要求。实现这一目标的一种方法是使用多个云。然而，在多云环境中管理应用程序是一项昂贵且复杂的任务，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，这将有助于评估性能（响应时间或吞吐量）和利用多云的软件系统的可用性。这些技术和工具将有助于软件供应商提前规划并以具有成本效益的方式管理计算资源。该建议包括（i）开发和验证新模型，以评估云中应用程序的性能和可用性;（ii）开发工具，以帮助建模过程;（iii）在多云环境中优化部署和提供应用程序，以最大限度地降低成本，并满足其性能和可用性要求;（iv）移动的应用的计算卸载，以提高它们的性能并降低移动的设备的电池功耗。* 这项研究工作的成果，如果成功，将有助于提高软件系统的质量和降低商业成本。加拿大的这些发展可以帮助软件行业在这里进行战略定位，并帮助其在全球范围内发展。

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.**