Azure Backup File Size

Question

Azure Backup File Size

Oguzhan Keten 1

I experienced file size growth after installation and backup with Azure Backup MARS agent. For example, after the backup was made, the area occupied by the file in Azure was 50, but after 1-2 hours it suddenly went up to 70. What is the reason of this?

SadiqhAhmed-MSFT 49,326 Reputation points Microsoft Employee Moderator

2022-04-19T09:49:30.687+00:00

Hello @Oguzhan Keten Thank you for reaching out to us at Microsoft Q&A community platform. Happy to assist you!

As I understand your concern is with Azure backup size. Initially it was 50 thereafter it increased to 70. Just want to highlight on few aspects of Azure backup.
Azure backup always takes full backup for the first time and the consecutive backups are incremental.
Azure backup takes snapshot of the data and transfers that data to the vault. The data is compressed when it is finally transferred to the vault.

Few checks to isolate the issue:
Was this a first backup (Full) or a schedule backup?
What is the size of the data you are backing up to Azure using Azure Backup MARS agent?
When you checked the backup size (50) was the backup completed?

Can you check the job completed to know the size of the data transfer?
Also, check the backup schedule to understand when the backup is getting triggered.
Appreciate if you could share the screenshot of backup console that shows difference in backup size.
Oguzhan Keten 1 Reputation point

2022-04-19T09:54:13.507+00:00

Hello,
The problem occurred on 2 clients after the first backup. The customer's data size was around 100 GB, after taking the first full backup, the backup size decreased to 50, and when I checked later, this data increased to 70.
Oguzhan Keten 1 Reputation point

2022-04-19T09:54:51.32+00:00

Hello,
The problem occurred on 2 clients after the first backup. The customer's data size was around 100 GB, after taking the first full backup, the backup size decreased to 50, and when I checked later, this data increased to 70.
SadiqhAhmed-MSFT 49,326 Reputation points Microsoft Employee Moderator

2022-04-19T12:34:41.99+00:00

If I understand correctly, the total size of data is 100 GB, after full backup it showed as 50 GB and then changed to 70 GB. If this is true, then I would say, it is expected. Because, during snapshot phase or data transfer to vault phase you must have noticed 50 GB, after completion of data transfer it changed to 70 GB. So, the 100 GB data size after transfer to vault is showing as 70 GB post compression which is an expected behavior.

Please correct me If I have misunderstood your question here.
Oguzhan Keten 1 Reputation point

2022-04-19T12:49:05.5+00:00

I understand,
So, is this happening because of the synchronous difference between the portal and the service?
SadiqhAhmed-MSFT 49,326 Reputation points Microsoft Employee Moderator

2022-04-19T14:21:21.43+00:00

Usually this doesn't happen in most cases.

Are you observing this issue only with 2 clients? If yes, what about the other machines?
Oguzhan Keten 1 Reputation point

2022-04-19T14:40:35.747+00:00

Yes, we only met with 2 customers and then we never met.

1 answer

Your answer

SadiqhAhmed-MSFT 49,326 Reputation points Microsoft Employee Moderator

2022-04-19T09:49:30.687+00:00

Hello @Oguzhan Keten Thank you for reaching out to us at Microsoft Q&A community platform. Happy to assist you!

As I understand your concern is with Azure backup size. Initially it was 50 thereafter it increased to 70. Just want to highlight on few aspects of Azure backup.
Azure backup always takes full backup for the first time and the consecutive backups are incremental.
Azure backup takes snapshot of the data and transfers that data to the vault. The data is compressed when it is finally transferred to the vault.

Few checks to isolate the issue:
Was this a first backup (Full) or a schedule backup?
What is the size of the data you are backing up to Azure using Azure Backup MARS agent?
When you checked the backup size (50) was the backup completed?

Can you check the job completed to know the size of the data transfer?
Also, check the backup schedule to understand when the backup is getting triggered.
Appreciate if you could share the screenshot of backup console that shows difference in backup size.
Oguzhan Keten 1 Reputation point

2022-04-19T09:54:13.507+00:00

Hello,
The problem occurred on 2 clients after the first backup. The customer's data size was around 100 GB, after taking the first full backup, the backup size decreased to 50, and when I checked later, this data increased to 70.
Oguzhan Keten 1 Reputation point

2022-04-19T09:54:51.32+00:00

Hello,
The problem occurred on 2 clients after the first backup. The customer's data size was around 100 GB, after taking the first full backup, the backup size decreased to 50, and when I checked later, this data increased to 70.
SadiqhAhmed-MSFT 49,326 Reputation points Microsoft Employee Moderator

2022-04-19T12:34:41.99+00:00

If I understand correctly, the total size of data is 100 GB, after full backup it showed as 50 GB and then changed to 70 GB. If this is true, then I would say, it is expected. Because, during snapshot phase or data transfer to vault phase you must have noticed 50 GB, after completion of data transfer it changed to 70 GB. So, the 100 GB data size after transfer to vault is showing as 70 GB post compression which is an expected behavior.

Please correct me If I have misunderstood your question here.
Oguzhan Keten 1 Reputation point

2022-04-19T12:49:05.5+00:00

I understand,
So, is this happening because of the synchronous difference between the portal and the service?
SadiqhAhmed-MSFT 49,326 Reputation points Microsoft Employee Moderator

2022-04-19T14:21:21.43+00:00

Usually this doesn't happen in most cases.

Are you observing this issue only with 2 clients? If yes, what about the other machines?
Oguzhan Keten 1 Reputation point

2022-04-19T14:40:35.747+00:00

Yes, we only met with 2 customers and then we never met.

Answer 1

As mentioned earlier, if the full backup with data size 100 GB, it is expected to be around 65-70 GB in Azure after compression. I don't see a problem in your case. IMO, that is the expected behavior. Refer to the FAQ page - https://learn.microsoft.com/en-us/azure/backup/backup-azure-backup-faq#why-is-the-size-of-the-data-transferred-to-the-recovery-services-vault-smaller-than-the-data-selected-for-backup-

If you are keen to know/understand if there was data fluctuation, we can perform deep dive technical investigation by logging a support request to Azure technical support team. The ticket enables you to work closely with the support engineers and get a quick resolution to your issue.

Here is the link - https://learn.microsoft.com/en-us/azure/azure-portal/supportability/how-to-create-azure-support-request to create support case.

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Azure Backup File Size

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