Eric Sproul of OmniTI speaks on ZFS Day http://zfsday.com/zfsday/
How does one go about running intensive business-intelligence (BI) database queries on rapidly changing data? We found ourselves pondering this question while helping Etsy do periodic reporting on their massive BI database. We harnessed the power of ZFS to create lightweight, yet writable, clones of production data that could be deleted when the report was done. The side effect was that we could also stand up staging environments at any time to test upgrades, schema changes and anything else that needed to be validated against real data.