Consider an arbitrary distributed network in which large numbers of
objects are continuously being created, replicated, and destroyed. A
basic problem arising in such an environment is that of organizing a
*data tracking scheme* for locating object copies. In this
paper, we present a new tracking scheme for locating nearby copies of
replicated objects in arbitrary distributed environments.

Our tracking scheme supports efficient accesses to data objects while keeping the local memory overhead low. In particular, our tracking scheme achieves an expected polylog(n)-approximation in the cost of any access operation, for an arbitrary network. The memory overhead incurred by our scheme is polylog(n) times the maximum number of objects stored at any node, with high probability. We also show that our tracking scheme adapts well to dynamic changes in the network.