Re: [dm-devel] [PATCH 0/4] dm verity: add support for error correction

[Sami Tolvanen]

On Fri, Nov 06, 2015 at 10:05:24PM +0100, Zdenek Kabelac wrote:
> So how do you want to correctly 'restore'  missing full sectors
> with just 0.8% data overhead ??

We use interleaving. Each byte in a 4k block is part of a different
Reed-Solomon block, which means an entire lost 4k data block looks like a
single error. When we also spread the bytes that form a single Reed-Solomon
block across the partition, we end up being able to correct several
megabytes of consecutive corrupted blocks with very small space overhead.

Sami
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