High availability solutions for transactional database systems

Nowadays production flows are modular, each module in the enterprise being specialized and used to achieve a particular task. In many cases the modules are interconnected and materials are sequentially processed in each module resulting a final, unique product or assembly. One typical such production module is a flexible cell/system using multiple robots. In such complex enterprise environments, providing continuous services for applications is a key component of a successful implementing of robotized manufacturing. High availability (HA) is one of the components contributing to continuous service provision for applications, by masking or eliminating both planned and unplanned downtime of systems and applications. This is achieved by eliminating hardware and software single points of failure (SPOF). The systems configured for high availability are a combination of hardware and software components configured to work together to ensure automated recovery in case of failure with a minimal acceptable downtime. A high availability solution will ensure that the failure of any component of the solution either hardware, software or system management, will not cause the application and its data to become permanently unavailable. High availability solutions should eliminate single points of failure through appropriate design, planning, hardware selection, software configuring, application control, carefully environment control and change management discipline. In short, one can define high availability as the process of ensuring an application is available for use by duplicating and/or sharing hardware resources managed by a specialized software component. A high availability solution in robotized manufacturing provides automated failure detection, diagnosis, application recovery, and node (robot controller) re integration. The chapter discusses the implementing of a high availability solution in a robotized manufacturing structure (cell, line). The solution is based on a High Availability Linux Cluster which is responsible for data availability and preservation on a NFS (Network File System) file system, and a second cluster – Fabrication Cluster (FC) which runs on Adept robot controllers, developed under the V+ programming language.

In recent decades, virtualization as an abstraction from physical hardware has become a popular solution to resource isolation and server consolidation. With the surge in adoption of virtualization technologies, ensuring High Availability (HA) for applications hosted in virtualized environments emerges as an important problem and has garnered substantial attention. In this paper, we present a brief comparison of virtualization technologies from a HA perspective. The state-of-the-art HA solutions in two mainstream types of virtualized platforms (i.e., hypervisor-based platform and container-based platform) are respectively investigated in terms of limitations and features such as live migration, failure detection, and checkpoint/ restore. One of our key findings is that, compared with hypervisor-based platforms, HA features in container-based platforms are far from enough. From a HA perspective, extensions on top of container technologies are required.

In the last chapter, we talked about some basic things about MVCC in PostgreSQL, and what is bloat in the database and how it can be removed. We explained how autovacuum helps in removing bloat and improving performance. We also covered the best practices to execute maintenance activities like vacuum, reindex in detail. In this chapter, we will talk about the importance of High Availability (HA), and what information we need to build an HA solution and the procedures to implement it in PostgreSQL. We will cover some open source and enterprise tools to implement HA. We will also cover the importance of a pooler, and available poolers on the market and their implementation.

As an important IT infrastructure, website is a system which requires high reliability and availability levels. Website meets the criteria as a highly available system because website must provide services to clients in real time, handle a large amount of data, and not lose data during transaction . A highly available system must meet the condition of being able to run continuously as well as guaranteeing consistency on data requests. This study designed a website with high availability. The approach was building network cluster with failover and replicated block device functions . Failover was built to provide service availability, while replicated block device provides data consistency during failure of service . With failover cluster and replicated block device approaches, a cluster which is able to handle service failures of web server and database server on the website. The result of this study was the services of the website could run well if there was any failure in node members of the cluster. The system was able to provide 99,999 (five nines) availability on database server services and 99,98 (three nines) on web server services .

The authors developed a diagnostic radiology display station that makes use of a minimal GUI. The display paradigm is based on concepts identified by Krupinski and other sand the authors' experience with earlier display stations both in the military and commercial environments. A comparison with this display paradigm and the more common paradigms in use in current commercial display will be given. The advantages and disadvantages of each will be discussed. The display station was implemented using off the shelf hardware and software components. It is based on the Windows NT operating system. The software supports up to four monitors in a portrait configuration with a resolution of 2.5K X 2K. The display station presents the radiologist with a dark and non-distracting reading background. It supports the most frequently used display operations through a mouse interface, without standard GUI icons, buttons, menus and lists. Display of reports and reading lists is supported via commercial HIS/RIS interface engines. Clinical usage result from a beta test at the Hospital of the University of Pennsylvania will be presented. Early results indicate that the minimal GUI paradigm improves workflow and increases reading speed. However, the improvement in workflow was out- weighted by the display station's lack of integration with a HIS/RIS.

Implementing and debugging high-performance network subsystems is a challenging task. In this paper, we present our experiences from developing and debugging a network interface card (NIC). Our NIC targets networked storage subsystems (Marazakis et al., 2006). For this purpose it mainly provides support for remote direct-memory-access (RDMA) write, sender-side notification of RDMA write completion, and receiver-side interrupt generation. In our work we examine issues that arise during system implementation and debugging, both in terms of correctness as well as performance. We present an analysis of the individual problems we encounter and we discuss how we address each case. For most problems we encounter, it is not possible to rely on existing debugging tools. However, we find that most of the techniques we use in this process, rely on collecting some form of event records from software or hardware components. We believe that such capabilities can be provided for independent hardware or software components in isolation, a fairly straight-forward task, thus, significantly simplifying the debugging process in complex systems of this nature

The economics of semiconductor manufacturing have forced process engineers to develop techniques to increase wafer yield. Improvements in process controls and uniformities in all areas of the fab have reduced film thickness variations at the very edge of the wafer surface. This improved uniformity has provided the opportunity to consider decreasing edge exclusions, and now the outermost extents of the wafer must be considered in the yield model and expectations. These changes have increased the requirements on lithography to improve wafer edge printability in areas that previously were not even coated. This has taxed all software and hardware components used in defining the optical focal plane at the wafer edge. We have explored techniques to determine the capabilities of extreme wafer edge printability and the components of the systems that influence this printability. We will present current capabilities and new detection techniques and the influence that the individual hardware and software components have on edge printability. We will show effects of focus sensor designs, wafer layout, utilization of dummy edge fields, the use of non-zero overlay targets and chemical/optical edge bead optimization.

MOPS is a platform for surgical robotics research. It consists of hardware and software components for building surgical robot systems based on existing robot arms. The reference system presented in this paper has two robot arms, each with an adapter for mounting and actuating different types of surgical instruments. Additionally, the system has a high-resolution stereo camera and a simple operator console with haptic devices and foot pedals for teleoperating the manipulators. Software components are based on Robot Operating System (ROS) to keep them modular and reusable for different types of hardware. We evaluate the precision of our system for vision-based tasks and demonstrate its potential for surgical task automation. The mean end-to-end error, including that of the vision system, for a trajectory following task was 1.2mm / 0.3° for one manipulator and 2.7mm / 0.7° for the other. MOPS software and hardware components are made available under an open-source license to encourage collaboration and facilitate the advancement of surgical robotics research.

A large class of modern distributed file systems treat metadata services as an independent system component, separately from data servers. The availability of the metadata service is key to the availability of the overall system. Given the high rates of failures observed in large-scale data centers, distributed file systems usually incorporate high-availability (HA) features. A typical approach in the development of distributed file systems is to design and develop metadata services from the ground up, at significant cost in terms of complexity and time, often leading to functional shortcomings. Our motivation in this paper was to improve on this state of things by defining a general-purpose architecture for HA metadata services (which we call RMS) that can be easily incorporated and reused in new or existing file systems, reducing development time. Taking two prominent distributed file systems as case studies, PVFS and HDFS, we developed RMS variants that improve on functional shortcomings of the original HA solutions, while being easy to build and test. Our extensive evaluation of the RMS variant of HDFS shows that it does not incur an overall performance or availability penalty compared to the original implementation.

인터넷 환경의 급속한 발전과 더불어 국내외 미션 크리티컬한 비즈니스 환경이 온라인에 의해 서비스 되고 있다. 따라서 웹 환경을 통해 처리되어야 할 정보의 양의 급증과, 이의 처리를 위해 여러 개의 단일 서버를 고속의 네트워크로 연결한 고가용성 구현이 가능한 클러스터 컴퓨팅 시스템이 등장하게 되었다. 그 결과 클러스터 기반 DBMS에 관한 연구와 상용화된 솔루션을 통해 국내외적으로 활발히 진행 중이며, 이에 따라 클러스터 기반 DBMS를 효율적이고 최적화된 상태의 관리 연구는 미흡한 실정이다. 따라서 본 논문에서는 클러스터 기반 DBMS를 위한 고가용성 클러스터 솔루션의 최적화된 관리 기법과 이론에 대해 알아본다. In these days, Internet environment are very quickly development as well On-line service have been using a online for the mission critical business around the world. As the amount of information to be processed by computers has recently been increased there has been cluster computing systems developed by connecting workstations server using high speed networks for high availability. As a result, this study on a cluster based DBMS and common solution of DBMS venders has been studying with a wide range, as well as It is not good study a management skill for the cluster-based DBMS efficiently and optimization. accordingly, This study find out optimization managements skill and theory of he High availability solution on cluster-based DBMS.

Broadband Power Line Communications (BPL) is a technology that has proved to be a very suitable option for the deployment of Smart Grid solutions. It provides a low cost, proprietary, high performance future-proof backhaul between Secondary Substations. This paper will focus on the description of the different "Fault Cases" that might occur in medium voltage BPL communication architecture and their consequent High Availability solution, taking advantage of Iberdrola's experience in the use and maintenance of this technology along its large scale Smart Grid deployment. The description of the High Availability functionality and the results of the tests developed so far are presented in this paper so that utilities might find it useful to provide an added value in their own Smart Grid deployments.

Cloud computing provides virtual resources so that end-users or organizations can buy computing power as a public utility. Cloud service providers however must strive to ensure good QoS by offering highly available services with dynamically scalable resources. HA-OSCAR is an open source High Availability (HA) solution for HPC/cloud that offers component redundancy, failure detection, and automatic fail-over. In this paper, we describe HA-OSCAR as a cloud platform and analyze system availability of two potential cloud computing systems, OSCAR-V cluster and HA-OSCAR-V. We also explore our case study to improve Nimbus, a popular cloud IaaS toolkit. The results show that the system that deploys HA-OSCAR has a significantly higher degree of availability.

This article is part of the extensive research of value characteristics of IT community and their potential for innovative development. In view of this, the author examines the problem of determination of the modern cultural situation and, as a result, deduction of the criterion that establishes what “modern” is. Based on the previously acquired conclusions (according to which, such criterion is the consideration of irreducible multiplicity, and the major risk is the loss of autonomy by individuals), the author aims to find the model of subjectivity that would be simultaneously multiple and autonomous. The search for the model that meets such criterion is carried out through referring to the control technologies developed within the framework of third-order cybernetics. The novelty of this article consists in peculiarity of the approach towards solution of the set task: the question in the form and method of determination of modernity has been first raised and  solved within the framework of the Russian academic philosophical community at  the previous stage of research, which determines the relevance at the current stage as well. Comparison of the developments of Russian and foreign authors reveals the parallelism between the development of cybernetics and psychoanalysis; demonstrates the conceptual intersections of the third-order cybernetics and schizoanalysis; establishes the conformity between the subjectivity of the individual and the type of organizations they are engaged in. The article offers the concept of “dividual” as a model suitable for solution of the set task. The conclusions is made that the existing potential of the IT community for modernization is neutralized in the context of transition towards the hierarchical structure of the organization.

This paper explores the ethical issues related to publication, authorship, and mentoring with the goal of better defining coauthorship standards and encouraging research ethics discussion and education within the academic civil engineering research community. Graduate students, junior and tenured faculty, technicians, administrators, and field practitioners in the civil engineering research community need to address the evolving ethical issues in multiple-authored and mentor-supervised publications. By using a five-step interrelated research methodology, the authors examine the current factors affecting the academic research environment and describe some of the unspoken but ethically questionable practices in the academic community. Most tangible rewards are on the basis of a faculty member's or researcher's publication record, and the increasing pressure to produce publications earlier and more often in the academic's career exacerbate the problem of a lack of clarity in ethical standards for multiauthored publications. The timing and frequency standards associated with publications for tenure, promotion, and continuing research funding opportunities result in academics' maximization of the number of research efforts taken to publication, with the number of authors per scientific publication steadily increasing. Further, as the number of authors has increased, the level of contribution of each coauthor to the research project and publication decreases. Data show that it is impossible to detect or assume equal-effort contributions by coauthors or their knowledge-base about the project design, findings, or implications. This paper proposes a threefold ethical framework for evaluating and analyzing the ethical norms for authorship status. It is the hoped that this thought-paper stirs the waters of this important issue to maintain the solidarity and integrity of engineering research activities and publications.

The public transport system of New South Wales (NSW), Australia is impotent to receive 100% of the fare from light rail and buses due to the unavailability of a continuous real-time monitoring system. This scheme thereby seeks to help update the NSW public transport ticket collection system, with the aid of a counter that will be integrated into the public transportation within the Ticket Tapping Machine, to provide passenger count against the number of touches occurring at each stop; and thus, increasing the revenue. The product comprises of hardware and software components - the hardware system is located within the public transport while the software system incorporating a web portal is positioned for the authorities to have access to the real-time passenger data. At the hardware end, the ultrasonic sensors and the raspberry pi would detect the number of passengers on the transport and the LCD screen would display the number of passengers who had not tapped their smart card ticket. Additionally, the raspberry pi module used in the hardware component can denote the transportation location with the help of an in-built Wi-Fi component. With this designed technology, the authorities would be able to monitor and record the movements of the passenger in real-time system addressing the existing challenges faced by the NSW public transport authority, especially in the case of light rail and buses being used for free by certain passengers.