Immutable Backups and retention with incremental forward forever

[BRogers]

Dear team,

I just set up my first direct S3 backup to Backblaze with object lock.
It is set to incremental forever by default.
Just to be sure:
If I have set 15 days immutable, but keep 30 versions in the backup job (incremental forever), does Veeam still ensure that the required blocks/data for the last 15 versions are kept immutable, even if they are older than that?

Thanks for your help.

[sfirmes]

Welcome to the forums.

Which version of VBR are you using? Also, are you using a SOBR or a stand-alone repository?

[vitalii.fesh]

Veeam reviews and extends immutability (if needed) every 10/30 days. This process is called block generation.
https://helpcenter.veeam.com/docs/vbr/u ... tml?ver=13

[sfirmes]

Vitalii, block generation is used to help reduce I/O operations and associated costs incurred by the customer. It is during subsequent backup jobs where VBR will review and extend the immutability of an object if needed. Block generation shouldn't be used when configuring the duration of immutability.

In the scenario above if you have 30 days of backup retention set and you want to have the backups immutable for the entire backup retention period, you should set the immutability duration to be 30 days as well.

[BRogers]

Thank you very much for the anwer.

@Steve: Does this mean, I should set the immutability duration always one day higher as my full backup history? So keep history=21 should then have immutable for 22 days?

If I have ummutable settings for 3 days, but 20 days of veeam versions, does that mean in case of s3 deletion veeam could still restore the last 3 days completly(full backup)?

I do backup directly to s3.

Thank you

[vitalii.fesh]

In the scenario above if you have 30 days of backup retention set and you want to have the backups immutable for the entire backup retention period, you should set the immutability duration to be 30 days as well.

So, eventually, my backups will be locked for 30 + 30 = 60 days based on the formula: Actual retention = job retention policy + immutability period.

I believe we should set immutability to 5–10 days, as this guarantees that at any point during that period, the backup chain is protected. In this scenario, the actual retention would be the configured retention plus those additional 5–10 days, instead of 30. Do you agree?

[sfirmes]

Vitalii,

If you are using V12 of VBR the actual object retention is 70 days, assuming you're using the default block generation setting of 10 days. As the link I posted notes the formula for "actual object retention" is Actual Object Retention = job retention policy + immutability period + Block Generation period.

We modified the formula for V13 of VBR for actual object retention. There are multiple formulas used in V13, so I recommend you check out the link above since it does a great job explaining the possible scenarios and the applicable actual object retention formula used.

Hope this helps.