Compare AFTER backup has run

[sowen222]

 

 

My backup died during the 'compare' stage. It's probably fine, but I have NO way of doing a compare to verify that everything really did make it to the backup. Verify media only checks it's readable, which is not the same thing.

 

 

 

The only way to be sure, is to re-run the backup - which takes 6 hours :-/

 

 

 

Please add an option to do a COMPARE at a later time, like *every* other backup program has.

 

 

 

Why this isn't already a part of Retrospect, I have no idea.

[kaisa]

Yes. I encountered that too. Problems, hang up during compare and then I was not sure if it was really ok. Please include an extra compare. If files have changed I can see it in the error log

[jordannolan]

Second the motion

[queball]

OR a better idea is to calculate a CRC for the file during the initial backup stage and then during the compare stage it just has to check against the CRC calculated earlier freeing the need for the network to verify the tape. (maybe verify already does this and its just not made clear that the original backup includes built in detection of corrupt files)

 

Of course there may be Patent issues since I have seen BRU on Unix does things like this.

[natew]

Hi

 

It isn't a CRC but here is what would happen in this case:

 

when you do a verify on a backup set it verifies that the data and the catalog file and the data on the backup media match. It also verifies that the media is readable.

 

In you subsequent backups Retrospect compares files that are on the backup target disk to the information in the catalog file. If there are any mismatches the file is backed up again.

 

In other words - both backup operations and the verify operation use the catalog file as a basis for checking data validity. Any discrepancies will be picked up in the next backup.

 

Nate