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Abstract. Deduplication is widely accepted as an effective technique for eliminating duplicated data in backup and archival systems. Nowadays, deduplication is also becoming appealing in cloud computing, where large-scale virtualized storage infrastructures hold huge data volumes with a significant share of duplicated content. There have thus been several proposals for embedding deduplication in storage appliances and file systems, providing different performance trade-offs while targeting both user and application data, as well as virtual machine images. It is however hard to determine to what extent is deduplication useful in a particular setting and what technique will provide the best results. In fact, existing disk I/O micro-benchmarks are not designed for evaluating deduplication systems, following simplistic approaches for generating data written that lead to unrealistic amounts of duplicates. We address this with DEDISbench, a novel micro-benchmark for evaluating disk I/O performance of block based deduplication systems. As the main contribution, we introduce the generation of a realistic duplicate distribution based on real datasets. Moreover, DEDISbench also allows simulating access hotspots and different load intensities for I/O operations. The usefulness of DEDISbench is shown by comparing it with Bonnie++ and IOzone open-source disk I/O micro-benchmarks on assessing two open-source deduplication systems, Opendedup and Lessfs, using Ext4 as a baseline. As a secondary contribution, our results lead to novel insight on the performance of these file systems.

This paper endeavours in comprehending the processes of production and reproduction of content in the social networking site Tumblr under the guise of Battaile's theory of expenditure and the aspects of homogeneity and heterogeneity in post-totalitarian societies. The main focus is the analysis of blogs connected trough the social networking site Tumblr, in a diverse rage of categories, from the amateuristic production of content to the reproduction of culture media products, but always concern with the transgressor nature of the apropriation of pornographic and/or erotic ideas.

Neste artigo pretendemos aproximar e articular os conceitos de espetáculo, de Guy Debord, e de situação-limite, de Karl Jaspers, afim de transpor certas aporias com os quais o pensamento debordiano se enfrenta, confronta e transforma numa época que se desenha como tecnocrática e na qual os meios de comunicação e informações tornam-se ubíquos e os sujeitos, mediados e mediadores, se veem transformados por uma vivência na presença e através desses meios.