Re: convert old full + differentials into new full

On Fri, 16 Apr 2021 21:39:24 +0200
Denis Corbin <[email protected]> wrote:

>
> Or maybe making a mix, having several raw of incremental (I) backups
> based on the same full (F) backup, (D standing for an incremental
> based on the full thus a "Differential" backup):
> 
> F+D-I-I-I-I
>  |
>  +D-I-I-I-I
>  |
>  +D-I-I-I-I
> 
> F+...
> 
> There is no best solution for all cases, it always depends on the
> context/environment/"data life".
> 

I think I have a better solution for my purposes: use rsync to update
an off-line, possibly remote mirror of the sources quickly, then use dar
to archive that mirror to slow secondary storage.  I don't have to
worry too much about the speed at which I can rescue the most recent
backup from dar, since the rsync mirror serves that purpose.  Also, the
on-line-intrusive operation is an incremental rsync update of the
mirror, which is fast (provided access to the mirror is fast, of
course).  Hence I don't have to worry about doing an occassional slow
and intrusive large dar differential backup.  This solution requires
more storage, but probably is the least intrusive of on-line
operations.  I also get to choose whether to have the rsync mirror and
dar archive be remote or just the dar archive be remote.  That depends
on the network speed vs. local disk speed and availability, as well as
the safety of having the mirror local vs. remote.