[OpenIndiana-discuss] vdev reliability was: Recommendations for fast storage

[Jim Klimov]

On 2013-04-18 15:57, Edward Ned Harvey (openindiana) wrote:
> I think you're misplacing a decimal, confusing bits for bytes, and mixing up exponents.  Cuz you're way off.
>
> With merely 70 unknown *bits* that is, less than 10 bytes, you'll need a 3-letter government agency devoting all its computational resources to the problem for a few years.

Uh... I'll raise a white flag and say I'm too preoccupied now to really
go into math and see which one of us is wrong. Indeed, however, my post
was based on practical experiment with a few values to test in each
location (about 2^2 variants instead of 2^8 for a full-byte match), so
here's a few orders of magnitude in complexity difference right away ;)

So likely you're more correct, and solution of the problem is then out
of practical boundaries even for a small corruption, except for true
single-bit rots (if these are at all possible after CRC corrections).

BTW, in terms of the amount of matching checksums - does it matter if
we are talking about just a 70-bit string or about the same string at
a fixed location in the 4kb or 128kb block?

//Jim