Browsing by Author "Aikema, David"
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- ItemOpen AccessAn Assessment of the VOMS and GridShib VO Management Systems(2007-03-01) Aikema, David; Kiddle, Cameron; Simmonds, RobIn the past, high performance computing consortia in Canada have received separate grants for resources. Furthermore, a consortium s resources have been primarily intended for users local to member institutions of the consortium. Recently, the seven high performance computing consortia in Canada worked together on a successful single CFI (Canadian Foundation for Innovation) grant proposal, called the National Platform Fund. While users will still be expected to try to meet computing needs from their local consortium first, there will be a greater emphasis on the national sharing of resources. With a much larger user base nationally, mechanisms for authenticating users and authorizing access to resources need to be explored.
- ItemOpen AccessA model of account access control and lifecycle management(2008-02-04) Aikema, DavidThis document introduces an RDF-based model describing the access control and lifecycle management policies of service providers. It is based upon the model structure proposed in my M.Sc. thesis [4]. This model is centered around a service provider s view of systems, and the agreements that they may reach with either individual users or virtual organizations, representing aggregations of users. This document is structured as follows. First of all, the modelling languages and tools used in the creation of the model are introduced. Secondly, a high-level overview of the model will be presented, and the composition of the following chapters will be discussed.
- ItemOpen AccessOptimizing Data Centre Energy and Environmental Costs(2013-05-01) Aikema, David; Simmonds, RobertData centres use an estimated 2% of US electrical power which accounts for much of their total cost of ownership. This consumption continues to grow, further straining power grids attempting to integrate more renewable energy. This dissertation focuses on assessing and reducing data centre environmental and financial costs. Emissions of projects undertaken to lower the data centre environmental footprints can be assessed and the emission reduction projects compared using an ISO-14064-2-compliant greenhouse gas reduction protocol outlined herein. I was closely involved with the development of the protocol. Full lifecycle analysis and verifying that projects exceed business-as-usual expectations are addressed, and a test project is described. Consuming power when it is low cost or when renewable energy is available can be used to reduce the financial and environmental costs of computing. Adaptation based on the power price showed 10-50% potential savings in typical cases, and local renewable energy use could be increased by 10-80%. Allowing a fraction of high-priority tasks to proceed unimpeded still allows significant savings. Power grid operators use mechanisms called ancillary services to address variation and system failures, paying organizations to alter power consumption on request. By bidding to offer these services, data centres may be able to lower their energy costs while reducing their environmental impact. If providing contingency reserves which require only infrequent action, savings of up to 12% were seen in simulations. Greater power cost savings are possible for those ceding more control to the power grid operator. Coordinating multiple data centres adds overhead, and altering at which data centre requests are processed based on changes in the financial or environmental costs of power is likely to increase this overhead. Tests of virtual machine migrations showed that in some cases there was no visible increase in power use while in others power use rose by 20-30W. Estimates of how migration was likely to impact other services used in current cloud environments were derived.
- ItemOpen AccessVO-centric account management(2007) Aikema, David; Simmonds, Robert William JohnVirtual organizations (VOs) are now being used by major grid computing projects such as LCG, associated with CERN's Large Hadron Collider, to reduce the cost and complexity of user management. Users may be able to gain access to resources at a service provider, based on attributes supplied by a virtual organization which has negotiated an access agreement with this service provider. A survey of existing virtual organization management and account management tools shows that these tools address access control through the passing of attributes in variĀous forms. However, these tools provide only limited support for lifecycle management features such as the mapping of new users to accounts, management of renewals, and handling of account expiry. A model of account access control and lifecycle management is presented which capĀtures current system behaviours and sets a roadmap illustrating useful ways in which these tools may be extended.