DistCp (distributed copy) is a tool used for large inter/intra-cluster copying. It uses Map/Reduce to effect its distribution, error handling and recovery, and reporting. It expands a list of files and directories into input to map tasks, each of which will copy a partition of the files specified in the source list.
The erstwhile implementation of DistCp has its share of quirks and drawbacks, both in its usage, as well as its extensibility and performance. The purpose of the DistCp refactor was to fix these shortcomings, enabling it to be used and extended programmatically. New paradigms have been introduced to improve runtime and setup performance, while simultaneously retaining the legacy behaviour as default.
This document aims to describe the design of the new DistCp, its spanking new features, their optimal use, and any deviance from the legacy implementation.