Database High Availability As A Service For Cloud Computing

Title from PDF of title page, viewed on August 23, 2016Dissertation advisor: Vijay KumarVitaIncludes bibliographical references (pages 115-122)Thesis (Ph.D.)--School of Computing and Engineering. University of Missouri--Kansas City, 2016On conventional database systems, the recovery manager applies transaction Undo or Redo operation or a combination of them to recover the last consistent state of the database from a system failure. Transaction redo, compared to undo, helps to shorten the system downtime so the execution of transactions is managed in such a way that majority of transactions require redo to recover the database. To further reduce the recovery time, the recovery module uses “Checkpoint” operation. Even though it is possible to eliminate transaction redo altogether, the conventional system architecture, however, is not capable to deploy innovative approaches. The availability of “Virtual” machines on cloud has given us an architecture that makes it possible to completely do away with transaction redo which allows us to eliminate the effect of system or transaction failure by taking the database to the next consistent state. In this dissertation, we present a novel scheme of eliminating the effect of such failures by applying transaction “roll-forward.” Our approach intelligently applies roll-forward from the point of failure which removes the effect of system failure on the database. We refer to our system as AAP (Always Ahead Processing). In AAP a transaction always executes to completion. We have made forward execution of transactions persistent by combining together transaction execution, transaction failure and its subsequent recovery as one seamless operation. Unlike legacy recovery scheme, in our approach transactions roll forward from the point of failure while concurrently executing other transactions. As a result, system downtime during recovery is eliminated. The end result is a database system with high availability and fault-tolerance. Our work enables cloud providers to offer transactional HA-DBMS (Highly Available – DataBase Management System) as an option that too with multiple data sources not necessarily only relational. AAP is independent of the underlying cloud architecture and therefore can be used in different type of cloud settings like public, private, hybrid or federated. In a federated cloud, the location of the physical host machine(s) is very important for fast and responsive HA (High Availability) service. We designed and developed a tool that will aid AAP to find the nearest physical host. We call this tool IGOD (Identification of Geolocation of clOud Datacenter). Apart from aiding AAP in a federated cloud, IGOD is an independent tool and can also be used for enforcing privacy and security in cloud datacenters; in particular for HIPAA compliant data storage. Our prototype demonstrates AAP’s HA, fault tolerance and the elimination of system downtime during recovery from a failure.Introduction -- Literature review -- DBHAaaS - AAP -- Identification of Geolocation of Cloud Datacenter -- Conclusion and future wor

A formal agent-based personalised mobile system to support emergency response

Communication may be seen as a process of sending and accepting information among individuals. It is a vital part of emergency response management, sharing the information of situations, victims, family and friends, rescue organisations and others. The obtained contextual information during a disaster event, however, is often dynamic, partial and may be conflicting with each other. Current communication strategies and solutions for emergency response have limitations - in that they are often designed to support information sharing between organisations and not individuals. As a result, they are often not personalisable. They also cannot make use of opportunistic resources, e.g. people nearby the disaster-struck areas that are ready to help but are not a part of any organisation. However, history has told us such people are often the first responders that provide the most immediate and useful help to the victims. On the other hand, the advanced and rich capabilities of mobile smartphones have become one of the most interesting topics in the field of mobile technologies and applied science. It is especially interesting when it can be expanded to become an effective emergency response tool to discover affected people and connect them with the first responders and their families, friends and communities. At present, research on emergency response is ineffective for handling large-scale disasters where professional rescuers could not reach victims in disaster struck-areas immediately. This is because current approaches are often built to support formal emergency response teams and organizations. Individual emergency response efforts, e.g. searching for missing people (inc. families and friends), are often web-based applications that are also not effective. Other works focus on sensory development that lacks integrated search and rescue approaches. In this thesis, I developed a distributed and personalisable Mobile Kit Disaster Assistant (MKA) system that is underpinned by a formal foundation. It aims at gathering emergency response information held by multiple resources before, during and after a large-scale disaster. As a result, contextual and background information based on a formal framework would be readily available, if a disaster indeed strikes. To this end, my core contribution is to provide a structural formal framework to encapsulate important information that is used to support emergency response at a personal level. Several (conceptual) structures were built to allow an individual to express his/her own individual circumstances, inc. relationships with others and health status that will determine how he/she may communicate with others. The communication framework is consisting of several new components: a rich and holistic Emergency Response Communication Framework, a newly developed Communication and Tracking Ontology (CTO), a newly devised Emergency Response Agent Communication Language (ER-ACL) and a brand-new Emergency Response Agent Communication Protocol (ER-ACP). I have framed the emergency response problem as a multi-agent problem where each smartphone would act as an agent for its user; each user would take on a role depending on requirements and/or the tasks at hand and the above framework is aimed to be used within a peer to peer distributed multiagent system (MAS) to assist emergency response efforts. Based on this formal framework, I have developed a mobile application, the MKA system, to capture important features of EM and to demonstrate the practicalities and value of the proposed formal framework. This system was carefully evaluated by both domain experts and potential users of targeted user groups using both qualitative and quantitative approaches. The overall results are very encouraging. Evaluators appreciated the importance of the tool and believe such tools are vital in saving lives – that is applicable for large-scale disasters as well as for individual life-critical events