Attaining the Promise and Avoiding the Pitfalls of TCP in the Datacenter.

Over the last several years, datacenter computing has become a pervasive part of the computing landscape. In spite of the success of the datacenter computing paradigm, there are significant challenges remaining to be solved--particularly in the area of networking. The success of TCP/IP in the Internet makes TCP/IP a natural candidate for datacenter network communication. A growing body of research and operational experience, however, has found that TCP often performs poorly in datacenter settings. TCP's poor performance has led some groups to abandon TCP entirely in the datacenter. This is not desirable, however, as it requires reconstruction of a new transport protocol as well as rewriting applications to use the new protocol. Over the last few years, promising research has focused on adapting TCP to operate in the datacenter environment. We have been running large datacenter computations for several years, and have experienced the promises and the pitfalls that datacenter computation presents. In this paper, we discuss our experiences with network communication performance within our datacenter, and discuss how we have leveraged and extended recent research to significantly improve network performance within our datacenter.