On Wed, May 7, 2014 at 12:40 PM, Richard Pieri <[email protected]> wrote: > Dan Ritter wrote: >> 3Ware tw_cli man page: >> >> Verify activity attempts to verify all units based on their unit >> type. Verifying RAID-1 involves checking that both drives contain the > > It doesn't work reliably. If the data is corrupted somewhere in the > controller itself (flakey cache for example) then the checksums will be > correct but the data that is written and checked is wrong. I've had a > 3Ware controller do this to me. All of the checksums matched up but the > data was damaged prior to the calculations and writes. Correctly written > and replicated wrong data is still wrong data. :P
And checksums can be incorrectly generated/verified by any hardware at any time. I claim that 100% data integrity is impossible. I don't think even ZFS can guarantee 100% data integrity with the right set of bizarre hardware failures in the CPU/RAM of the computer. Pointing out that all hardware can have errors is kind of a moot point. More important is being able to assess what kinds of hardware/software failures can result in loss of integrity (or data) and their relative probabilities. Bill Bogstad _______________________________________________ Discuss mailing list [email protected] http://lists.blu.org/mailman/listinfo/discuss
