On Sun, Jan 15, 2012 at 04:06:33PM +0000, Peter Tribble wrote:
> On Sun, Jan 15, 2012 at 3:04 PM, Jim Klimov <jimkli...@cos.ru> wrote:
> > "Does raidzN actually protect against bitrot?"
> > That's a kind of radical, possibly offensive, question formula
> > that I have lately.
> Yup, it does. That's why many of us use it.

There's actually no such thing as bitrot on a disk.  Each sector on
the disk is accompanied by a CRC that's verified by the disk
controller on each read.  It will either return correct data or report
an unreadable sector.  There's nothing inbetween.

Of course, if something outside of ZFS writes to the disk, then data
belonging to ZFS will be modified.  I've heard of RAID controllers or
SAN devices doing this when they modify the disk geometry or reserved
areas on the disk.

-Gary Mills-            -refurb-                -Winnipeg, Manitoba, Canada-
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