Immutable backup in Backblaze B2

[DVelez]

Hi!
I’m currently testing immutable backups with Backblaze B2, and I’ve noticed something that doesn’t quite add up. The retention period applied to the files doesn’t seem to match the retention configured in the repository.

For example, the repository is set with an immutability period of 5 days, but when I check the files in Backblaze, they appear to be locked for nearly 20 days.

Do you know why the repository’s immutability setting would differ from what’s actually being stored?

[david.domask]

Hi DVelez,

Which version of Veeam are your currently on and what did you set for retention on the job?

Very likely this is about Block Generation and the immutability model selected for the repository.

I would give a read on the Block Generation link as it explains it a bit more; the immutability is extended a bit to reduce overall API calls to handle immutability and ensure that immutability is maintained for the backup chain.

[DVelez]

Hello David,
Thanks for sharing those links. The customer is currently running Veeam v13, with Backblaze B2 set up as an S3-compatible repository.

For this test, we’re aiming for 15 days of immutability. I’ve set the repository’s minimum immutable period to 5 days. Does that mean the total immutability would be 15 days (5 days from the repository + 10 days from Backblaze B2 Object Lock), or am I misunderstanding how these two settings interact?

[david.domask]

Mmm, when you say "Backblaze B2 Object Lock", do you mean you have a default immutability set on the B2 side? Or you're referring to the block generation?

Basically, only Veeam should control / set the immutability, don't use the S3 built-in life-cycle rules / whatever for setting immutability.

And to answer more specifically, as noted it depends a bit on your configuration, so without further information it will be hard to advise.

Check the scenarios here and give a read on the actual immutability, and then tell which scenario applies to you, as there are a few situations to consider.

But sounds like probably 5 days of minimum immutability period is what you're looking for, as with block generation that will set the desired 15 days.