help='which old versions to use for running the stress tests in upgrade mode. can be specified multiple times [options=4.2.0, 5.0.8, 5.2.7, 6.0.0, 6.1.0, 6.5.1, 6.6.3]')
help='directory containing old version environments (should contain 5.0.8/, 5.2.7/, etc, and the environments should be in those) [default=../../tokudb.data/stress_environments]')