How shall I do backups?

[ciphergoth]

OK, I've used DAR long enough to know that it's fundamentally broken. I just gave up on it at the point where I'd written CD 1 of a two CD archive, and said "please test the integrity of this slice of the archive". It responded "last slice is not present, please provide before integrity can be tested".

So I'm not using that any more.

What the hell can I use that does proper multi-archive backups for CDs?

Comments

comment from DAR's author

[(Anonymous)]

I like your feedback! By mistake I found it here. Sorry to reply to it:

for information, DAR does the test of a *whole* archive. After the "long enough time you've spent", I don't know where you have seen that it can make the testing of a single slice (this is a non sense as a given file inside the archive could be split between two or more slices, and CRC is computed file by file). As usual, dar starts by the first slice, then it needs the last.

OK, I Promise, if I find again (by mistake of course) one of your feedback, I will not reply to it :-)

Denis Corbin.

Re: comment from DAR's author

[ex-meta.livejournal.com]

Technically, it's perfectly possible to test each chunk of archive as you go. Just MD5 checksum the chunk as you write it, go back and re-read the data and compare the checksum.

Nothing wrong with file-by-file checksums, but you might as well waste 128 bits per CD and do a chunk-by-chunk checksum too to make the user's life easier.

Re: comment from DAR's author

[(Anonymous)]

yes, you are right, it could be possible to add a secondary CRC global to each slice. This would allow the testing of each slice individualy.

For me it is just a simple feature to add, not really the "mistake at the very deepest level of its design" I 've read previously. 8^D

Anyway, thanks for feedback.

Denis Corbin.

Re: comment from DAR's author

[ciphergoth.livejournal.com]

Sure, but I think it indicates that you and I think of slices in a different way. You mainly think about operating on all slices of the archive simultaneously. I generally don't have the disk space to store them all at once. You think of slices as fragments of a whole. I think of them as largely independent collections of file information that happened to come from the same archiving operation. I think my approach is the correct one because it makes an individual slice much more useful.

I thought you CRC'd each file separately, no?

Re: comment from DAR's author

[ciphergoth.livejournal.com]

*egg on face*

I'll write up my thoughts on what I think the ideal backup utility would look like at some point but I tend to think that while it can be nice to write to authors to say "here, your program can be improved like this", there's not a lot of point in saying "your program has a mistake at the very deepest level of its design" because there's not a lot they can do about it...

Still I will write it and send it to you. Once I've got speech recognition going. Once I've reinstalled windows. Once I've backed up the laptop... you see my problem...

DAR is still the best there is - if I want something better, me and meta will just have to write it! :-)