Manolis Marazakis

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Flash-based solid state drives (SSDs) offer superior performance over hard disks for many workloads. A prominent use of SSDs in modern storage systems is to use these devices as a cache in the I/O path. In this work, we examine how transparent, online I/O compression can be used to increase the capacity of SSD-based caches, thus increasing the(More)
Workloads in distributed database applications consist of queries and transactions. In order to address performance requirements, distributed transaction processing systems have to deal with two related issues: transaction routing and scheduling. Due to the distribution of data objects among nodes and the access cost incurred by remote accesses, efficient(More)
Modern storage systems are required to scale to large storage capacities and I/O throughput in a cost effective manner. For this reason, they are increasingly being built out of commodity components, mainly PCs equipped with large numbers of disks and interconnected of high-performance system area networks. A main issue in these efforts is to achieve high(More)
This paper discusses the requirements of current and emerging large-scale distributed applications and emphasizes the need for a common infrastructure to support them. A design for an infrastructure that aims at satisfying these requirements is presented. Moreover, it is shown how key aspects of important large-scale applications can exploit the services(More)
Workflow management systems are developed to support and automate the execution of business processes, by assigning tasks to agents according to the workflow specification. Current state-of-the-art workflow systems are mainly concerned with the routing and assignment of tasks, providing little support for tasks related to administration and management. This(More)
Large-scale scientific and business applications require data processing of ever-increasing amounts of data, fu-eling a demand for scalable parallel file systems comprising hundreds to thousands of disks. Modern parallel file system architectures however, span a large and complex design space. As a result, IT architects are faced with a challenge when(More)
The paper discusses dynamic workload management in transaction processing systems where the workload consists of multiple classes of units of work, including workflows comprised of interdependent tasks. Business requirements specify that differing levels of service must be provided to different classes of work, thus it is natural to specify performance(More)