Data Consistent Up- and Downstreaming in a Distributed Storage System

Distribution of large data objects among several storage servers is a common technique to speed up access rates. In combination with parity schemes, failures of single server nodes can be tolerated, so that such systems reach a certain degree of fault tolerance. In this paper such a distributed server system is analyzed. Data objects are stored in a data layout according to RAID level 3 among disk subsystems of different computers. An access control provides concurrent up- and down-streaming of data objects to/from the distributed storage system with ensured data consistency. This consistency control is described in combination with the handling of faulty server nodes and faulty clients. Furthermore, performance is measured with several access patterns. An application of that technique is for instance a distributed video server, allowing permanently updates without interrupting access.