  This paper proposes round-hashing, which is suitable for data storage on
distributed servers and for implementing external-memory tables in which each
lookup retrieves at most a single block of external memory, using a stash. For
data storage, round-hashing is like consistent hashing as it avoids a full
rehashing of the keys when new servers are added. Experiments show that the
speed to serve requests is tenfold or more than the state of the art. In
distributed data storage, this guarantees better throughput for serving
requests and, moreover, greatly reduces decision times for which data should
move to new servers as rescanning data is much faster.
