I had fun once diagnosing a bad bit in a drive's cache memory. Writes would go out, and sometimes come back with a bit set. All the disk-resident CRCs in the world won't help if your data is mangled before it makes it to the media.
File systems with end-to-end checking are good. (These can turn into accidental memory tests for your host, too, and with a large enough population you'll see interesting failures).
At the storage level there is T10 DIF that is supposed to help with such things (among many other things), though it is used in a very limited fashion and is only supported on the higher end disks.
File systems with end-to-end checking are good. (These can turn into accidental memory tests for your host, too, and with a large enough population you'll see interesting failures).