TY - GEN A1 - Schintke, Florian A1 - Reinefeld, Alexander A1 - Haridi, Seif A1 - Schütt, Thorsten T1 - Enhanced Paxos Commit for Transactions on DHTs N2 - Key/value stores which are built on structured overlay networks often lack support for atomic transactions and strong data consistency among replicas. This is unfortunate, because consistency guarantees and transactions would allow a wide range of additional application domains to benefit from the inherent scalability and fault-tolerance of DHTs. The Scalaris key/value store supports strong data consistency and atomic transactions. It uses an enhanced Paxos Commit protocol with only four communication steps rather than six. This improvement was possible by exploiting information from the replica distribution in the DHT. Scalaris enables implementation of more reliable and scalable infrastructure for collaborative Web services that require strong consistency and atomic changes across multiple items. T3 - ZIB-Report - 09-28 KW - Paxos KW - Transaktionen KW - DHT KW - strenge Konsistenz KW - Paxos KW - transactions KW - DHT KW - strong consistency Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11448 SN - 1438-0064 ER - TY - THES A1 - Schütt, Thorsten T1 - Synchronisation von verteilten Verzeichnisstrukturen N2 - Das Management von großen Datenmengen spielt eine immer wichtigere Rolle, wie aktuelle Entwicklungen in der Hochenergiephysik [2] zeigen. Für das DataGrid-Projekt zum Beispiel ist es notwendig, große Datenmengen auf mehrere Rechenzentren in Europa zu verteilen und die Daten untereinander zu synchronisieren. Auch innerhalb von Clustern gewinnen mit zunehmender Anzahl der Knoten Werkzeuge zur effizienten Synchronisation und Verteilung von Daten an Bedeutung. Im Rahmen dieser Arbeit wurde ein effizientes Verfahren zur Synchronisation von verteilten Verzeichnisstrukturen entwickelt und implementiert. Mit diesem Verfahren ist es möglich, unabhängige Änderungen an beliebigen Repositories gleichzeitig durchzuführen. Das Verfahren benötigt keine zentrale Instanz, wodurch eine gegenüber vielen existierenden Verfahren verbesserte Skalierbarkeit erreicht werden konnte. Dabei wurden Erkenntnisse aus der Graphentheorie eingesetzt und weiterentwickelt, um die Netzwerktopolo-gie und -handbreiten zwischen den Rechnern zu berücksichtigen. Durch die Verwendung einer Offline-Synchronisation werden Änderungen erst dann an andere Rechner propagiert, wenn der Nutzer dies anstößt. Das kann zum Beispiel nach einer abgeschlossenen Transaktion, die Änderungen an mehreren Dateien beinhaltet, angemessen sein. N2 - Current developments in high energy physics [2] show that the management of large datasets plays an important role. For the DataGrid project it is necessary to distribute large datasets over several computing centers all over Europe and to synchronize these datasets. Within clusters tools for efficient synchronization and distribution of data become more important, too. In this thesis, a method to synchronize distributed directory structures was developed and implemented which makes it possible to perform independent changes to arbitrary repositories simultaneously. This method needs no central instance and therefore the presented system achieves a better scalability than many existing systems. Knowledge from graph theory was used and improved to take the network topology and the network bandwidth between the computers into account. By using offline synchronization, changes will only be propagated when the user initiates it. This can be reasonable after a completed transaction which consists of changes on several files. Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-10071 ER - TY - GEN A1 - Moser, Monika A1 - Haridi, Seif A1 - Shafaat, Tallat A1 - Schütt, Thorsten A1 - Högqvist, Mikael A1 - Reinefeld, Alexander T1 - Transactional DHT Algorithms N2 - We present a framework for transactional data access on data stored in a DHT. It allows to atomically read and write items and to run distributed transactions consisting of a sequence of read and write operations on the items. Items are symmetrically replicated in order to achieve durability of data stored in the SON. To provide availability of items despite the unavailability of some replicas, operations on items are quorum-based. They make progress as long as a majority of replicas can be accessed. Our framework processes transactions optimistically with an atomic commit protocol that is based on Paxos atomic commit. We present algorithms for the whole framework with an event based notation. Additionally we discuss the problem of lookup inconsistencies and its implications on the one-copy serializability property of the transaction processing in our framework. T3 - ZIB-Report - 09-34 KW - Distributed System KW - DHT KW - Paxos KW - Algorithms KW - Storage Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-11532 SN - 1438-0064 ER - TY - THES A1 - Schütt, Thorsten T1 - Range queries in distributed hash tables Y1 - 2010 UR - http://www.dr.hut-verlag.de/978-3-86853-370-5.html ER - TY - CHAP A1 - Döbbelin, Robert A1 - Schütt, Thorsten A1 - Reinefeld, Alexander T1 - An Analysis of SMP Memory Allocators T2 - Proceedings of the 41st International Conference on Parallel Processing Workshops (Fifth International Workshop on Parallel Programming Models and Systems Software for High-End Computing (P2S2)) Y1 - 2012 U6 - https://doi.org/10.1109/ICPPW.2012.10 SP - 48 EP - 54 PB - IEEE Computer Society ER - TY - JOUR A1 - Kruber, Nico A1 - Högqvist, Mikael A1 - Schütt, Thorsten T1 - The Benefits of Estimated Global Information in DHT Load Balancing JF - Cluster Computing and the Grid, IEEE International Symposium on Y1 - 2011 U6 - https://doi.org/10.1109/CCGrid.2011.11 VL - 0 SP - 382 EP - 391 PB - IEEE Computer Society CY - Los Alamitos, CA, USA ER - TY - CHAP A1 - Schintke, Florian A1 - Reinefeld, Alexander A1 - Haridi, Seif A1 - Schütt, Thorsten T1 - Enhanced Paxos Commit for Transactions on DHTs T2 - CCGRID Y1 - 2010 U6 - https://doi.org/10.1109/CCGRID.2010.41 SP - 448 EP - 454 PB - IEEE ER - TY - CHAP A1 - Schütt, Thorsten A1 - Reinefeld, Alexander A1 - Schintke, Florian A1 - Hennig, C. T1 - Self-Adaptation in Large-Scale Systems: A Study on Structured Overlays Across Multiple Datacenters T2 - Architectures and Languages for Self-Managing Distributed Systems (SelfMan@SASO) Y1 - 2009 U6 - https://doi.org/10.1109/SASOW.2010.65 ER - TY - CHAP A1 - Schütt, Thorsten A1 - Moser, Monika A1 - Plantikow, Stefan A1 - Schintke, Florian A1 - Reinefeld, Alexander T1 - A Transactional Scalable Distributed Data Store T2 - 1st IEEE International Scalable Computing Challenge, co-located with CCGrid’08 Y1 - 2008 ER - TY - CHAP A1 - Schütt, Thorsten A1 - Reinefeld, Alexander A1 - Schintke, Florian A1 - Hoffmann, Marie T1 - Gossip-based Topology Inference for Efficient Overlay Mapping on Data Centers T2 - Peer-to-Peer Computing Y1 - 2009 U6 - https://doi.org/10.1109/P2P.2009.5284553 SP - 147 EP - 150 ER -