"Best guess" parameters in RAID recovery
Every once in a while, we get a feature request for our RAID recovery software (http://www.freeraidrecovery.com/) to implement the ability to interrupt the analysis midway and get a list of possible solutions, sorted by confidence level.
There is some strong reservation against this would-be feature.
Although it looks like a good idea, a very nice thing to have, it has some undesired consequences we cannot allow. The confidence thresholds are there for reason, and we put an effort to ensure they are balanced between faster analysis (lower thresholds) and reliability (higher thresholds). Once we make incomplete solutions accessible, people will start using these solutions on real data. Sooner than later, someone is going to destroy their RAID 5 by reassembling it on the controller using wrong parameters set. In RAID0, this would be no harm (just re-assemble again in correct order), but with RAID 5, incorrect assembly (automatically followed by a rebuild) destroys the array beyond any practical repair. This is similar to consuming unbaked or half-baked food. Sooner or later someone will get poisoned. Determining if RAID configuration is correct is even more difficult than telling baked food from raw meat.
There is some strong reservation against this would-be feature.
Although it looks like a good idea, a very nice thing to have, it has some undesired consequences we cannot allow. The confidence thresholds are there for reason, and we put an effort to ensure they are balanced between faster analysis (lower thresholds) and reliability (higher thresholds). Once we make incomplete solutions accessible, people will start using these solutions on real data. Sooner than later, someone is going to destroy their RAID 5 by reassembling it on the controller using wrong parameters set. In RAID0, this would be no harm (just re-assemble again in correct order), but with RAID 5, incorrect assembly (automatically followed by a rebuild) destroys the array beyond any practical repair. This is similar to consuming unbaked or half-baked food. Sooner or later someone will get poisoned. Determining if RAID configuration is correct is even more difficult than telling baked food from raw meat.
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