1615 - Block-based backup of Azure VMs: frequently asked questions

Modified on Tue, 5 Aug at 1:08 PM

Block-based backups enhance the way we store and restore Azure Virtual Machines by using Redstor’s Storage Platform instead of relying solely on Azure snapshots. This enables us to support complex configurations like SQL VMs, encrypted disks, striped RAID volumes, and other non-traditional file-based volumes.

To enable block-based backup for an Azure VM, switch on the toggle on the Backup schedule card. You will only be able to enable block-based backup if you also have Redstor Backup enabled.

Note: Block-based backups are currently only available to Early Access partners. As long as this feature is in Early Access, a third-party app user interface such as Backup Radar may not accurately reflect the status of block-based backups and restores. Customers are advised to confirm the results of backup and restore tests rather than relying solely on status indicators in a third-party app.

For more on backup and recovery of Azure VMs, see:

Frequently asked questions

Q: What happens to my existing (file-based) Azure VM backups once block-based backups are enabled?

A: Your new block-based backups will appear alongside your file-based backups. Existing backups will remain as is. Only new backups going forward will be block-based (assuming you have enabled the functionality on your VMs).

Q: Can I recover a VM using block-based backups?

A: Yes. We support recovery to a new VM via Full System Recovery (FSR).

Q: Can I recover to an existing VM instead of creating a new one?

No. Due to Azure constraints around resource conflicts and naming conventions, there is currently no option to recover block-based backups directly into a VM.

Q: Is file-level recovery supported for block-based backups?

Not yet. If you need to restore individual files, you should continue to use file-based backups or use native snapshot recovery.

Q: Can I switch back from block-based backups to file-based backups?

A: Yes. Customers can revert VMs back to file-based backups if needed.

Q: Will switching to block-based backups impact existing backup schedules or retention policies?

They should not be affected. Scheduling and retention for block-based backups work similarly to those for file-based backups, but customers should verify that the retention settings align with their requirements once they have made the switch.

Q: Do you support recovery to a different resource group, tenant, or VNet?

A: Yes, these restore targets are supported.

Q: Is malware scanning supported?

No, malware scanning is not currently supported for block-based backups.