On 8/4/06, Edward Shishkin <[EMAIL PROTECTED]> wrote:
Hans Reiser wrote:
> Edward Shishkin wrote:
>
>
>>Matthias Andree wrote:
>>
>>
>>>On Tue, 01 Aug 2006, Hans Reiser wrote:
>>>
>>>
>>>
>>>>You will want to try our compression plugin, it has an ecc for every
>>>>64k....
>>>
>>>
>>>
>>>What kind of forward error correction would that be,
>>
>>
>>
>>Actually we use checksums, not ECC. If checksum is wrong, then run
>>fsck - it will remove the whole disk cluster, that represent 64K of
>>data.
>
>
> 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..
Edward.
>
>>
>> and how much and
>>
>>
>>>what failure patterns can it correct? URL suffices.
>>>
>>
>>Checksum is checked before unsafe decompression (when trying to
>>decompress incorrect data can lead to fatal things). It can be
>>broken because of many reasons. The main one is tree corruption
>>(for example, when disk cluster became incomplete - ECC can not
>>help here). Perhaps such checksumming is also useful for other
>>things, I didnt classify the patterns..
>>
>>Edward.
>>
>>
Would the storage + plugin subsystem support storing >1 copies of the
metadata tree?
--
Greetz, Antonio Vargas aka winden of network
http://network.amigascne.org/
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