Re: [BackupPC-devel] BackupPC 4.0 features - attribute file and backup storage

[Fresel M. - hi c. e.U. <m.f...@hi...>]

hi Jeffrey,

posted "Thinking of 4.0 - change of compression level" afterwards suggesting creation of some kind of ".info" file

the SHA256 and SHA512 checksums would be included in that file
so would be the uncompressed size

the "file_naming" change would thus be irrelevant

Am 23.03.2011 um 19:40 schrieb Jeffrey J. Kosowsky:
> I don't see the advantage of having SHA256 and SHA512.
why not calculate them now (i.e when the server is idle?) to have it for future use?
who knows what rsync will be next year?
not within near future but: i.e. sha256 for blocks and sha512 for full file?
so we would have at least our full_file checksums present

> Let users choose one or the other.
can be realized by that info-file
it's still the user's decission on what additional checksums are created ....

> The only reason I proposed adding another
> checksum is if people are worried about MD5 collisions. So the goal
> would be to pick a 2nd checksum whether SHA256 or SHA512 or any other
> choice that the user believes to be sufficiently unique.
not really worried about colission but about file-integrity on the server's pooled file + time to recheck

today it's quite common to privide all 3 of them when downloading via web ....

> Having the uncompressed filesize may be nice but it is not critical to
> unique pool naming which after all is the purpose of the checksums.

might be implemented on some kind of "info" file

Greetings

Mike