Re: converting decremental to full backup

>On 01/06/2019 21:09, Matus UHLAR - fantomas wrote:
>> I have created a decremental backup and a full one, from older
>> time.
>>
>> Now I'd like to get rid of the full backup and convert the
>> decremental to full one. - in fact the opposite what I did when I
>> created the decremental backup.
>>
>> I have tried:
>>
>> dar -+  -A full -@ decremental -/ Oo # to try overwriting deta in
>> full archive with data from decremental archive
>>
>> I have tried replacing -A and -@, change -Oo to -Pp
>>
>> but either I get incremental/decremental backup, or I get the full
>> backup containing new files.
>>
>> is it possible to create old full debug without extracting both
>> backups?

On 02.06.19 12:03, Denis Corbin wrote:
>yes it is:
>
>assuming:
>- - at time 1 you have created a full backup named full1
>- - at time 2 you have created a second full backup named full2
>- - then just after you created a decremental backup decr1 which will
>replaces full1 (dar -+ decr1 -A full1 -@full2 -ad ...)
>- - you then deleted full1 as you now have decr1

exactly like that, I went through the docs and examples ...

>Your question is: how to recreate full1 using full2 and decr1, right?
>
>Just use this:
>
>dar -+ressurected_full1 -A full2 -@ decr1 full-from-diff
>
>full-from-diff target is defined in /etc/darrc and should be fetched
>by  by dar unless you add -N option.
>
>- ---
>full-from-diff:
>- -/ '{!(~I)}[Rr] {~S}[O*] P* ; {~s}[*o] *p'
>- ---

... but seems I didn't do through the docs deeply enough ...

>For the details, this overwriting is applied when a entry is found on
>both archives and means:
>- - "{!(~I)}" = if the entry in decr1 is not an inode, then "[Rr]" = do
>not add any entry in the resulting archive: The entry in decr1 is a
>"detruit" object that flag the file to be removed when restoring
>decr1, this is a file that was added at time 2.
>- - else "{~S}" = if the entry in decr1 is a fully saved one, "[O*]" =
>take it in the resulting archive else "P*" = use the entry from full2:
>file  has not changed between time 1 and 2, it is thus completely
>saved in full2 as it is a full backup
>- - for EA and FSA: "{~s}" = if the EA/FSA is fully saved in decr1 take
>it in the resulting archive else take the on from full2 which is
>always fully saved (full backup).

... because they seemed too cryptic for me.
but now, I hope it's documented and can be found in the net.

>last in case there is no conflict the overwriting policy does not
>apply, this should only occur if a file has been removed from time 1
>to time 2 which means a entry fully saved and only present in decr1,
>such entry is then added to the resulting archive, as expected.
>
>The situation where an entry is only present in full2 should not
>arrive: such entry would have been created at time 2 and doing the
>decremental backup, a "detruit" entry would have been added into decr1
>to indicate this entry to be removed from filesystem when restoring
>decr1 over full2, thus the overwriting policy would be triggered as
>explained above leading to completely ignore such entry.
>
>I hope the explanation are not too confusing :-)

I don't think so.
Thank you!
-- 
Matus UHLAR - fantomas, [email protected] ; http://www.fantomas.sk/
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