Detecting bitrot with incremental repair

[John Sumsion]

jbellis talked about incremental repair, which is great, but as I understood, 
repair was also somewhat responsible for detecting and repairing bitrot on 
long-lived sstables.

If repair doesn't do it, what will?

Thanks,
John...


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Re: Detecting bitrot with incremental repair

[Robert Coli]

On Thu, Sep 11, 2014 at 9:44 AM, John Sumsion sumsio...@familysearch.org
wrote:

 jbellis talked about incremental repair, which is great, but as I
 understood, repair was also somewhat responsible for detecting and
 repairing bitrot on long-lived sstables.


SSTable checksums, and the checksums on individual compressed (and only
compressed) partitions provide some of this functionality, at very least
giving some visibility into bitrot style corruption.


 If repair doesn't do it, what will?


Read repair will help, but only repair is capable of providing the
guarantee you need. Probably Cassandra needs partition checksums on
uncompressed partitions, and then to mark a sstable un-repaired when it
detects a corrupt read.

=Rob