Help sizing up immutable storage

[xrowtenma]

Hi Guys,

We currently have a single job configured with 8 restore points, it’s a reverse incremental job, but this only runs every Friday, so there is 8 weeks of retention.

The current full backup file is 15 TB in size, increment files are approx. 300 GB.

If we were to set the immutability to a period of 8 or 9 weeks, what would the expected backup size be? (We currently use approx. 17 TB)

Will it leave all 8 weeks of backups alone, and perform a full backup after 9 weeks?

We are worried it will massively exceed our current storage limits (50TB limit) and are trying to document the outcome before making the change.

In the back end storage we see 8 files (as expected), but we see 1 x full Veeam file (15TB) and 7 x reversed incremental files (approx. 300GB each). Is this normal? I would have thought we would just see a single file as the reversed increments would just be injected in to the 15TB file?

I've logged it with support but haven't had any solid information on it.


Thanks!

[HannesK]

Hello,
setting immutability longer than the retention is a bad idea as we cannot delete it anyway. So I recommend to set immutability at least 10 days shorter than the retention. Without going too much into details: we optimize costs by extending immutability every 10 days. So immutability is often a bit longer than configured.

Back to your question: with default settings for reverse incremental (no active full backup), the size on object storage will be around the same as on your current storage.

Upload to object storage is forever incremental. Please see the sticky FAQ.

For information on backup modes, there are animations in KB1799 and the user guide also describes them.

Best regards,
Hannes

PS: I asked support to close case #05308556, because it's a "how-to" question and not a "it's broken" question

[xrowtenma]

Hi Hannes,

Thanks for the reply.

So if our backup retention is 8 weeks, on a reverse incremental job, if we say 8 x 7 days = 56 days, and we set the immutability to 46 days, then does that mean that we won't consume any more storage than normal?

Also, what would happen if we had a ransomware attack on day 100 for instance? The first full backup file will be out of the immutability window, so I assume this data can be destroyed, and only the last 46 days of incremental files would be protected (which I guess would be useless without the full backup file).


Thanks.

[HannesK]

Hello,

d we set the immutability to 46 days, then does that mean that we won't consume any more storage than normal?

correct.

Also, what would happen if we had a ransomware attack on day 100 for instance?

all restore points of the last 46 days would be protected by S3 object lock. Restore points at the age between 47 and 56 days would be lost. The exact amount of lost restore points depends on that 10 days extension of immutability. The important thing to know is: if 46 days are configured, then at least 46 days are always protected by object lock.

Note: in object storage there are only objects. No files. There are no backup modes in object storage. It's only restore points and the objects associated with that restore point.

Best regards,
Hannes

[xrowtenma]

Thanks again Hannes,

So I guess the only thing we need to understand now is the first full backup file.

If on day 1 the full file is created, and everything after that is reverse incremental, after day 47 this full backup file could be compromised, correct?

The 46 days of restore points wouldn't be of any use, as they rely on the first full backup from day 1?


Thanks!

[HannesK]

Hello,

and everything after that is reverse incremental

in object storage there are no backup modes. no forward, no reverse, no nothing incremental It's objects that form a restore point. I you like, you can dig into it, but I would just forget about backup modes in object storage. the closest analogy would be "forward incremental with daily space-less synthetic full".

At least the last 46 days are protected, if 46 days are configured.

Best regards,
Hannes

[Kim29]

Need to assist my understand. if I set immutable 7Days and Create Backup policy 14 days, I can sizing base on http://rps.dewin.me/ that don't need to consume more backup disk right?

[HannesK]

more or less "yes". maybe add three days because of the 10 days explanation I made above. As nobody knows real values in advance, I would just go with 14 days and call it a day.