I wrote my answer thinking about the XOR implementation. With reed-solomon
and single replication, the cases that need to be considered are indeed
smaller, simpler.

It seems I was wrong about my last statement though. If the machine hosting
a single-replicated block is lost, it isn't likely that the block can't be
reconstructed from a summary of the data. But with a RAID6 strategy / RS,
its is indeed possible but of course up to a certain number of blocks.

There clearly is a case for such tool on a Hadoop cluster.

Bertrand Dechoux
On Mon, Jul 21, 2014 at 2:35 PM, Zesheng Wu <[EMAIL PROTECTED]> wrote:
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