J E Beasley

OR-Library is a collection of test data sets for a variety of OR problems.

A full list of the test data sets available in OR-Library can be found here.

Lot sizing

OR-Library does not have any test problems for the lot sizing problem.

Some instances that appear to be no longer available used to be found at: http://www.core.ucl.ac.be/~wolsey/lotsizel.htm