Understanding Snapshot vs Item Level

[HenryA]

Good day all.

I have a question in Re: the M365 snapshot vs item level backups. I believe I understand the premise, but something I would like to clear up:

Do both options grab the data from as far back as you have in your account? Example: I have a mailbox with 6 years worth of e-mail, let's say from 2017 > I create a backup job to a repository that has 3 year snapshot policy retention with daily snapshots. Am I correct in assuming it will pull down all 6 years worth of E-mail, create a snapshot every day, and then 3 years in the future, delete the snapshots that start falling away from 3 years? (for example, in 2026, it will delete every old snapshot that's older than 3 years and will delete every daily snapshot older than 3 years? (and the cycle continues, new snaps are created, old snap deleted, but the first 3 years no snaps are deleted)

Is this correct?

Is Item Level the same idea, except it's every item older than 3 years?

OR

Is Item level grabbing the initial backup only 3 years behind? (meaning it will ignore e-mails older than 3 years, and never back them up in the first place)

I'm almost positive scenario one is correct, but a lot of confusing information online, would appreciate some clarification.

Thanks

[Mildur]

Hello Henry

Welcome to the forum.

For snapshot Level --> Correct, we will backup the entire content and keep the daily snapshot of the mailbox for 3 years.

Is Item level grabbing the initial backup only 3 years behind? (meaning it will ignore e-mails older than 3 years, and never back them up in the first place)

This statement is correct. Item Level backup checks the "creation time or last modification time" of each item and only protects those items which are in the configured retention.
3 years means, Today minus 3 years. Every Item which was created or changed between August 17th 2020 and August 17th 2023.
Items which are older than 3 years (created and changed) will not be protected and deleted from the backup repository when the retention job runs.

We have it documented in our user guide:
https://helpcenter.veeam.com/docs/vbo36 ... tml?ver=70

Best,
Fabian

[HenryA]

Hello Fabian.

Thank you for your reply. So just to confirm, if I am understanding you correctly, If I have a mailbox of 6 years worth of e-mails, let's say 2017. If I create an Item Level backup with retention of 3 years, it will only backup items created or modified 3 years ago, and ignore everything else (so it would only backup 2020 and up, and not backup 17,18,19).

On the other hand, a snapshot backup with 3 year retention will backup everything down to 2017 (whatever earliest data it can find), and then it will just keep creating snaps until the first 3 years rolls by, when it will start deleting snaps older than 3 years.

Theoretically that means a snapshot backup will backup everything in the initial backup, but start deleting after 3 years. Item Level backup, on the other hand, if I want to backup data from down to 2017, I have to select a 6 year retention.

Is this correct?

[Mildur]

If I create an Item Level backup with retention of 3 years, it will only backup items created or modified 3 years ago, and ignore everything else (so it would only backup 2020 and up, and not backup 17,18,19).

Correct.
One exception, calendar and contacts items can be excluded from being processed by the retention policy. Meaning, all of those objects are protected, even if they are older than 3 years:
https://helpcenter.veeam.com/docs/vbo36 ... tml?ver=70

On the other hand, a snapshot backup with 3 year retention will backup everything down to 2017 (whatever earliest data it can find), and then it will just keep creating snaps until the first 3 years rolls by, when it will start deleting snaps older than 3 years.

Correct. A snapshot of the entire mailbox content. Everything in it will be backed up and stored in the backup repository. The snapshot will be kept for 3 years.

Item Level backup, on the other hand, if I want to backup data from down to 2017, I have to select a 6 year retention.

Yes. Correct.

My recommendation:
- Backup and Recovery of entire mailboxes: Use snapshot level retention.
- Archiving each item/item version for a specified amount of time: Use item level retention.

Best,
Fabian

[HenryA]

This is perfect, Fabian!! Thank you for confirming this

[HenryA]

I have another question:

Let's say I ran a backup with Item Level Retention for 3 years, and it completed backing up. If I switch the retention level of that repository from 3 years to 6 years, will it then download and backup the older files? Or would I have to make a new repo with the 6 year retention?

[Mildur]

Switching the retention is not possible. You need to decide from the beginning which retention you want to use. If you want to switch the retention type, you need to start with a new backup repository.

Best,
Fabian

[HenryA]

Hi Mildur.

I can see that one can switch the retention level # in the settings. What happens if I select 6 years instead of 3 years, and save it?

[Mildur]

Ah, yes. I apologize, a misunderstanding from me of the question.
You can switch the retention period from 3 to 6 years. But you cannot change the retention type from item to snapshot.

When you change the retention period from 3 to 6 years, the next backup job session will also backup additional items older than 3 years, but not older than 6 years.

Best,
Fabian