Re: [Duplicity-talk] Concept and how to combine incremental and full backups to save space

[Scott Hannahs]

Yes, you can use the " --full-if-older-than” option to automatically initiate a 
new full back up.  You can limit the storage to only keeping 1 full backup with 
the "remove-all-but-n-full 1” command.

HOWEVER, it is logically impossible to do a second full backup if there isn’t 
space.  The only other method is removing the old backup first and then doing a 
new backup.  But if that new backup fails for any reason you are SOL so it 
isn’t a good idea.  For security of your backups you should have enough room 
for two full backups and a bunch of incremental.

As a suggestion, using an offsite commercial service can give you that 
flexibility without too much cost.  I use Wasabi and pay about $4/month/TB.  I 
have no interest in the Wasabi company other than a customer.  Once I set up 
the buckets and the S3 connection it has pretty much run on its own.  I do a 
full backup every 30 days and nightly incremental.

-Scott

> On Mar 17, 2022, at 4:41 AM, c.buhtz--- via Duplicity-talk 
> <duplicity-talk@nongnu.org> wrote:
> 
> Hello together,
> 
> I am sorry for asking because I assume the answers are still out there. But I 
> wasn't able to find the needed information's or I wasn't able to understand 
> them and bring them together in my head.
> 
> In the duplicity docs it is recommended to not make the chain of incremental 
> backup's to long. Make it one month and then do a full backup. OK, I 
> understand why.
> Technically I do not know how to "implement" this. Can I combine 
> switches/options that way that I only need one duplicity call and duplicity 
> decide itself if it has to do a incremental or full backup?
> 
> Currently I call duplicity with this (folders replaced by placeholders):
> 
> duplicity SOURCE_FOLDER file:///DESTINATION_FOLDER --no-encryption --progress 
> --verbosity INFO --volsize 500
> 
> I have very limited space on the destination. I think I am not able to hold 
> two full backups there. I only can have one full backup at time.
> 
> This is my current collection status where I have one (old) full and lot of 
> incremental.
> 
> Last full backup date: Fri Dec  3 09:44:22 2021
> Collection Status
> -----------------
> Connecting with backend: BackendWrapper
> Archive dir: /home/user/.cache/duplicity/50d0997d52a684176de033baca98f9f0
> 
> Found 0 secondary backup chains.
> 
> Found primary backup chain with matching signature chain:
> -------------------------
> Chain start time: Fri Dec  3 09:44:22 2021
> Chain end time: Thu Mar 17 09:23:28 2022
> Number of contained backup sets: 26
> Total number of contained volumes: 50
> Type of backup set:                            Time:      Num volumes:
>                Full         Fri Dec  3 09:44:22 2021                25
>         Incremental         Fri Dec  3 10:25:03 2021                 1
>         [snipped 20 incrementals]
>         Incremental         Tue Mar  8 08:45:37 2022                 1
>         Incremental         Thu Mar 10 11:25:11 2022                 1
>         Incremental         Wed Mar 16 17:41:44 2022                 1
>         Incremental         Thu Mar 17 09:23:28 2022                 1
> -------------------------
> No orphaned or incomplete backup sets found.
> 
> There is definitely not enough space to create a second full backup. Maybe I 
> can transform the incremental's into a second full so that there are no 
> incremental's anymore consuming space. When I have two fulls I can delete the 
> older one and go on with new incremental's (for one month). Is this a good 
> plan? :)
> 
> Kind
> Christian
> 
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