Abstract : Map/Reduce is a popular programming model and an associated implementation for processing large data sets nowadays. This report aims to present the problem of managing intermediate data which is generated during Map/Reduce computations. We focus on the Hadoop Map/Reduce framework and two file systems, Hadoop Distributed File System and BlobSeer File System, used as storage backends of Hadoop Map/Reduce framework, which substitute for the original intermediate storage layer. As a result, our new design deals with data reliability and efficiency, thanks to BlobSeer which supports access concurrency. The prototype has been experimented on the Grid'5000 testbed, using up to 150 nodes.