Enabling High Data Availability in a DHT

Many decentralized and peer-to-peer applications require some sort of data management. Besides P2P file-sharing, there are already scenarios (e.g. BRICKS project [3]) that need management of finer-grained objects including updates and, keeping them highly available in very dynamic communities of peers. In order to achieve project goals and fulfill the requirements, a decentralized/P2P XML storage on top of a DHT (Distributed Hash Table) overlay has been proposed [6]. Unfortunately, DHTs do not provide any guarantees that data will be highly available all the time. A self-managed approach is proposed where availability is stochastically guaranteed by using a replication protocol. The protocol recreates periodically missing replicas dependent on the availability of peers. We are able to minimize generated costs for requested data availability. The protocol is fully decentralized and adapts itself on changes in community maintaining the requested availability. Finally, the approach is evaluated and compared with replication mechanisms embedded in other decentralized storages.