Periodic Full Backups (new fresh backup chain)

[MAgno Santos]

Hello Everyone,

Fist of all: Amazing job with Proxmox VE and PBS. Very nice products.

My question basically is: How to set up a new fresh backup chain (full backup) without needing to create a new datastore?

 

[angelkiller]

Yes, this is a cool feature if we can setup a full backup on every second sunday and between do incremental in backup tasks.

 

[dcsapak]

i do not really understand, why do you want a 'full' backup again? this only wastes space.
also this makes little sense for the pbs architecture since the backups is split into chunks that get deduplicated.
theoretically you could upload all chunks again, but you would only overwrite the same data

if you verify your backups regularly (and optimally have redundancy in your storage, e.g. with zfs), there should be no problems with data integrity

 

[angelkiller]

But if there is anything after one year with the first full backup (corrupt sector on HDD) i think it is impossible get a restore working because every backup is linked to this corrupt first full backup. To avoid this it is a must to have a second PBS with sync and never do this with only one PBS in production.
Please correct me if i will be false with that.

 

[dcsapak]

i think it is impossible get a restore working because every backup is linked to this corrupt first full backup.

no only if that specific chunk is referenced by all backups, which will not happen if the data changes of this chunk

as i said, you can verify the backups regularly.
there are now patches applied where the client sends all chunks if the verify of the previous backup failed,
in that case either
* the new backup does not reference the corrupt chunk -> would have worked in any case
* the new backup does reference the corrupt chunk -> it now gets overwritten basically 'repairing' that chunk

 

[abien]

But if there is anything after one year with the first full backup (corrupt sector on HDD) i think it is impossible get a restore working (...)

The term backup chain does not apply to the way in which PBS works. There simply are no chains. There is chunks and indexes.
The basic assumption of "What if my data become corrupt" however is still a good thought. PBS counters this by using ZFS to make sure that no silent corruption of data can occur. Without going into to much technical details i will say this: If you take good care of your ZPOOL and verify your backups/chunks every once in a while you should not have to fear data corruption.

 

[MAgno Santos]

The term backup chain does not apply to the way in which PBS works. There simply are no chains. There is chunks and indexes.

So basically this is a question that simply does not make sense. Good to know

 

[oversite]

Hello Everyone,

Fist of all: Amazing job with Proxmox VE and PBS. Very nice products.

My question basically is: How to set up a new fresh backup chain (full backup) without needing to create a new datastore?

Perhaps if there really is a need for this, the reason could well be to have one "extra" full backup, it would make more sense to take this extra full backup using regular vzdump to another backup storage but the pbs. I don't see any other reason since pbs is chunk based.