Florian Schintke

Learn More
We present Scalaris, an Erlang implementation of a distributed key/value store. It uses, on top of a structured overlay network, replication for data availability and majority based distributed transactions for data consistency. In combination, this implements the ACID properties on a scalable structured overlay. By directly mapping the keys to the overlay(More)
Core grid technologies are rapidly maturing, but there remains a shortage of real grid applications. One important reason is the lack of a simple and high-level application programming toolkit, bridging the gap between existing grid middleware and application-level needs. The Grid Application Toolkit (GAT), as currently developed by the EC-funded project(More)
Large Grid systems not only provide massive aggregated computing power but also an unprecedented amount of distributed storage space. Unfortunately, the dynamic behavior of the Grid, caused by varying resource availability, unpredictable data updates, and the impact of local site policies makes it difficult to exploit the full capabilities of Data Grids. We(More)
ions like file movement that are independent of the underlying middleware infrastructure. The Grid Application Framework for Java (GAF4J) [33] is an application framework for multithreaded Java applications. GAF4J replaces thread objects by so-called task objects that can be executed on remote machines in a Grid. The GAT, however, has a broader(More)
We introduce SONAR, a structured overlay to store and retrieve objects addressed by multi-dimensional names (keys). The overlay has the shape of a multi-dimensional torus, where each node is responsible for a contiguous part of the data space. A uniform distribution of keys on the data space is not necessary, because denser areas get assigned more nodes. To(More)
Data lookup is a fundamental problem in peer-to-peer systems: Given a key, find the node that stores the associated object. Chord and other P2P algorithms use distributed hash tables (DHTs) to distribute the keys and nodes evenly across a logical ring. Using an efficient routing strategy, DHTs provide a routing performance of O(logN) in networks of N nodes.(More)
Consistent hashing is at the core of many P2P protocols. It evenly distributes the keys over the nodes, thereby enabling logarithmic routing effort 'with high probability'. However, consistent hashing incurs unnecessary overhead as shown in this paper. By removing consistent hashing from Chord, we derived a protocol that has the same favorable logarithmic(More)
We present a transaction processing scheme for structured overlay networks and use it to develop a distributed Wiki application based on a relational data model. The Wiki supports rich metadata and additional indexes for navigation purposes. Ensuring consistency and durability requires handling of node failures. We mask such failures by providing high(More)
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(More)