  Due to its advantages over traditional data centers, there has been a rapid
growth in the usage of cloud infrastructures. These include public clouds
(e.g., Amazon EC2), or private clouds, such as clouds deployed using OpenStack.
A common factor in many of the well known infrastructures, for example
OpenStack and CloudStack, is that networked storage is used for storage of
persistent data. However, traditional Big Data systems, including Hadoop, store
data in commodity local storage for reasons of high performance and low cost.
We present an architecture for supporting Hadoop on Openstack using local
storage. Subsequently, we use benchmarks on Openstack and Amazon to show that
for supporting Hadoop, local storage has better performance and lower cost. We
conclude that cloud systems should support local storage for persistent data
(in addition to networked storage) so as to provide efficient support for
Hadoop and other Big Data systems
