Immutability and Retention

[flomp]

There are a lot of questions regarding this topic already - however, they are often very specific and I was not really able to find an answer to my questions.

I created the following setup:

• SOBR with local disk storage as performance Tier and Wasabi S3 as Capacity Tier
• ON: Copy backups to object storage as soon as they are created
• ON: Move backups to object storage as they age out the op restore window
  Move Backup files older than 30 days
• For the Capacity Tier (Wasabi): Make recent backups immutable for 90 days
• Backup Job: Retention Policy: 50 days (no GFS, might enable this later)
• Backup Copy Job which copies from the SOBR to USB rotated drives which are replaced daily.

As far as I can tell from reading the forums, my immutability period is quite long. However, our data is not changing that much so I think this will work.

Questions:
- Is there any obvious wrongdoing in this configuration?
- Will there be any problems, because my immutability period (90 days) is longer than my retention policy (50 days)?
- Should I increase the retention policy?
- Am I right that such a long immutability period works for data that is not changing much?
- Any other comments?

Thanks!

[veremin]

Immutability period should be equal or shorter that the defined retention period. Otherwise the still immutable restore points will be removed from configuration database upon applying retetion, but still be present on object storage (that adds mess to storage management). So it's worth either increasing current retention or decreasing current immutability.

Not sure how immutability is related to frequency or amount of data changes, so can you elaborate on your question?

Thanks1

[flomp]

Ok thanks - I guess I will increase the retention. As soon as the data has been moved to the Capacity tier, it won't need much space on the local drive anyway.

Regarding immutability: As far as I understood (and by peeking into the contents of the bucket), the data is split into small parts (about 1MB) and stored by hash value. So: as long as the data does not change, there should be no additional space used. (Except for metadata, of course.) But of course, our data does change - I'll see how much it increases every day, once the initial upload to Wasabi is done. My guess is, that most of the new data is coming from Windows itself (Windows updates, logs, defrag, ...) as we only have small databases and office documents.

I was just a bit surprised that lots of people use relatively short (for my point of view) immutability periods like 7 or 14 days and would like to have some feedback if larger durations are reasonable or if I am exaggerating.

[veremin]

But object lock does not concern with amount of data changed, it simply marks all blocks corresponding restore point consists of locked for the required duration of time - the amount of blocks might be different, based on your change rate, but immutability does not care about that.

We recommend using immutability for the most recent backups, but nothing stops you from setting longer periods (just make according changes to the retention policy).

Thanks!