  Considerable Progress has been made in the last few years in improving the
performance of the distributed database systems. The development of Fragment
allocation models in Distributed database is becoming difficult due to the
complexity of huge number of sites and their communication considerations.
Under such conditions, simulation of clustering and data allocation is adequate
tools for understanding and evaluating the performance of data allocation in
Distributed databases. Clustering sites and fragment allocation are key
challenges in Distributed database performance, and are considered to be
efficient methods that have a major role in reducing transferred and accessed
data during the execution of applications. In this paper a review on Fragment
allocation by using Clustering technique is given in Distributed Database
System.
