Looking into why our S3 stuff wasn't deleting everything it should, I found it was a CS-side problem in develop as of commit 355e2f91. I can't say when it started happening. It is not currently happening in develop-1.2.
Running test000 once takes up about 7.2GB of disk space. Running it again, it should use the same 7.2GB, but instead uses about 12GB. It adds about 5GB of disk usage per run.
Some add'l info...
running as non-root
SKIP_OAM_INIT & starting with startcs/stopcs scripts