I once managed to use ZFS to detect a bit flip on a machine that did not have ECC RAM. All python programs started crashing in libpython.so on my old desktop one day. I thought it was a bug in ZFS, so I started debugging. I compared the in-memory buffer from ARC with the on-disk buffer for libpython.so and found a bit flip. At the time, accessing a snapshot through .zfs would duplicate the buffer in ARC, which made it really easy to compare the in-memory buffer against the on-disk buffer. I was in shock as I did not expect to ever see one in person. Since then, I always insist on my computers having ECC.