@misc{KolbeckHoegqvistStenderetal., author = {Kolbeck, Bj{\"o}rn and H{\"o}gqvist, Mikael and Stender, Jan and Hupfeld, Felix}, title = {Fault-Tolerant and Decentralized Lease Coordination in Distributed Systems}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-11658}, number = {10-02}, abstract = {Applications which need exclusive access to a shared resource in distributed systems require a fault-tolerant and scalable mechanism to coordinate this exclusive access. Examples of such applications include distributed file systems and master/slave data replication. We present Flease, an algorithm for decentralized and fault-tolerant lease coordination in distributed systems. Our algorithm allows the processes competing for a resource to coordinate exclusive access through leases among themselves without a central component. The resulting system easily scales with an increasing number of nodes and resources. We prove that Flease ensures exclusive access, i.e. guarantees that there is at most one valid lease at any time.}, language = {en} } @misc{MoserHaridiShafaatetal., author = {Moser, Monika and Haridi, Seif and Shafaat, Tallat and Sch{\"u}tt, Thorsten and H{\"o}gqvist, Mikael and Reinefeld, Alexander}, title = {Transactional DHT Algorithms}, issn = {1438-0064}, url = {http://nbn-resolving.de/urn:nbn:de:0297-zib-11532}, number = {09-34}, abstract = {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.}, language = {en} } @article{EnkeSteinmetzAdorfetal.2011, author = {Enke, Harry and Steinmetz, Matthias and Adorf, Hans-Martin and Beck-Ratzka, Alexander and Breitling, Frank and Br{\"u}semeister, Thomas and Carlson, Arthur and Ensslin, Torsten and H{\"o}gqvist, Mikael and Nickelt, Iliya and Radke, Thomas and Reinefeld, Alexander and Reiser, Angelika and Scholl, Tobias and Spurzem, Rainer and Steinacker, J{\"u}rgen and Voges, Wolfgang and Wambsganß, Joachim and White, Steve}, title = {AstroGrid-D: Grid technology for astronomical science}, series = {New Astronomy}, volume = {16}, journal = {New Astronomy}, number = {2}, doi = {10.1016/j.newast.2010.07.005}, pages = {79 -- 93}, year = {2011}, language = {en} } @article{KolbeckHoegqvistStenderetal.2011, author = {Kolbeck, Bj{\"o}rn and H{\"o}gqvist, Mikael and Stender, Jan and Hupfeld, Felix}, title = {Flease - Lease Coordination Without a Lock Server}, series = {Parallel and Distributed Processing Symposium, International}, volume = {0}, journal = {Parallel and Distributed Processing Symposium, International}, publisher = {IEEE Computer Society}, address = {Los Alamitos, CA, USA}, doi = {10.1109/IPDPS.2011.94}, pages = {978 -- 988}, year = {2011}, language = {en} } @inproceedings{StenderHoegqvistKolbeck2010, author = {Stender, Jan and H{\"o}gqvist, Mikael and Kolbeck, Bj{\"o}rn}, title = {Loosely Time-Synchronized Snapshots in Object-Based File Systems}, series = {Proceedings of the 29th IEEE International Performance, Computing, and Communications Conference}, booktitle = {Proceedings of the 29th IEEE International Performance, Computing, and Communications Conference}, publisher = {IEEE Computer Society}, doi = {10.1109/PCCC.2010.5682311}, year = {2010}, language = {en} } @inproceedings{SchaeferHoegqvist2012, author = {Sch{\"a}fer, Patrick and H{\"o}gqvist, Mikael}, title = {SFA : a symbolic fourier approximation and index for similarity search in high dimensional datasets}, series = {Proceedings of the 15th International Conference on Extending Database Technology}, booktitle = {Proceedings of the 15th International Conference on Extending Database Technology}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/2247596.2247656}, pages = {516 -- 527}, year = {2012}, language = {en} } @article{KruberHoegqvistSchuett2011, author = {Kruber, Nico and H{\"o}gqvist, Mikael and Sch{\"u}tt, Thorsten}, title = {The Benefits of Estimated Global Information in DHT Load Balancing}, series = {Cluster Computing and the Grid, IEEE International Symposium on}, volume = {0}, journal = {Cluster Computing and the Grid, IEEE International Symposium on}, publisher = {IEEE Computer Society}, address = {Los Alamitos, CA, USA}, doi = {10.1109/CCGrid.2011.11}, pages = {382 -- 391}, year = {2011}, language = {en} } @inproceedings{StenderKolbeckHoegqvistetal.2010, author = {Stender, Jan and Kolbeck, Bj{\"o}rn and H{\"o}gqvist, Mikael and Hupfeld, Felix}, title = {BabuDB: Fast and Efficient File System Metadata Storage}, series = {Storage Network Architecture and Parallel I/Os, IEEE International Workshop on}, booktitle = {Storage Network Architecture and Parallel I/Os, IEEE International Workshop on}, publisher = {IEEE Computer Society}, address = {Los Alamitos, CA, USA}, doi = {10.1109/SNAPI.2010.14}, pages = {51 -- 58}, year = {2010}, language = {en} } @inproceedings{BoeseAndrzejakHoegqvist2010, author = {B{\"o}se, Joos-Hendrik and Andrzejak, Artur and H{\"o}gqvist, Mikael}, title = {Beyond online aggregation: Parallel and incremental data mining with online Map-Reduce}, series = {Proceedings of the 2010 Workshop on Massive Data Analytics on the Cloud}, booktitle = {Proceedings of the 2010 Workshop on Massive Data Analytics on the Cloud}, publisher = {ACM}, address = {New York, NY, USA}, doi = {10.1145/1779599.1779602}, pages = {3:1 -- 3:6}, year = {2010}, language = {en} } @inproceedings{HoegqvistPlantikow2009, author = {H{\"o}gqvist, Mikael and Plantikow, Stefan}, title = {Towards Explicit Data Placement in Scalable Key/Value Stores}, series = {Architectures and Languages for Self-Managing Distributed Systems (SelfMan@SASO)}, booktitle = {Architectures and Languages for Self-Managing Distributed Systems (SelfMan@SASO)}, year = {2009}, language = {en} }