Edward Shishkin wrote:
> Tom Reinhart wrote:
>> Anyone with serious need for data integrity already uses RAID, so why
>> add brand new complexity for a solved problem?
>>
>> RAID is great at recovering data, but not detecting errors. File
>> system can detect errors with checksum. What is missing is an API
>> between layers for filesystem to say "this sector is bad, go rebuild
>> it."
>>
>
> Actually we dont need a special API: kernel should warn and recommend
> running fsck, which scans the whole tree and handles blocks with bad
> checksums.
Yes, but our fsck knows nothing about RAID currently so....
>
>> This seems like a much more simple and useful thing than adding ECC
>> into the filesystem itself.
>
> checksumming is _not_ much more easy then ecc-ing from implementation
> standpoint, however it would be nice, if some part of errors will get
> fixed without massive surgery performed by fsck
>
>
>>
>>
>>>>> How about we switch to ecc, which would help with bit rot not sector
>>>>> loss?
>>>>
>>>>
>>>>
>>>> Interesting aspect.
>>>>
>>>> Yes, we can implement ECC as a special crypto transform that inflates
>>>> data. As I mentioned earlier, it is possible via translation of key
>>>> offsets with scale factor > 1.
>>>>
>>>> Of course, it is better then nothing, but anyway meta-data remains
>>>> ecc-unprotected, and, hence, robustness is not increased..
>>>>
>>
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>>
>>
>
>
>
