[Box Backup] BadBackupStoreFile

[Ben Summers]

On Fri, 31 Aug 2007, Chris Wilson wrote:
>
> On Fri, 31 Aug 2007, Ben Summers wrote:
>
>
>>>> Another feature request: The backup server should (additionally)  
>>>> store
>>>> checksums across large blocks of files, e.g. 1MB blocks. Then  
>>>> only these
>>>> checksums need to be read from disk instead of the whole backup  
>>>> file.
>>>>
>>>
>>> I have a feeling that we already do, but I'm not 100% sure. Ben,  
>>> do you
>>> know?
>>>
>>
>> Checksums are per-block, encrypted. The block size depends on the  
>> size of the
>> file. You can do a compare using the checksums only using the -q  
>> option, and
>> only the checksums are read from disc and transferred over the  
>> network.
>>
>
> Do you know if we do that for diffing as well, or only for compare?


Well actually this feature was implemented to make efficient diffing  
possible with minimal network transfer. It was only later that it was  
(ab)used for a quick compare option.

So yes.

Ben