The Agent Does Not Generate Internal Sessions

Valid on Windows Hyper-V systems.

Symptom

When backing up data through pass through storage devices, the agent does not generate internal backup sessions.

Solution

This is expected behavior under the following conditions:

• The backup was submitted through a pass through storage device.
• The backup mode was one of the following:
• Mixed mode with the Allow file level restore option specified.
• Raw (full VM) mode with the Allow file level restore option specified.

Note: For more information about backup modes, see How Global and Local Backup Options Work.

Virtual hard disk (VHD or VHDX) files are files that are stored on Hyper-V systems that define the configuration of the volumes that reside on Hyper-V systems. Under most scenarios, Hyper-V virtual machines access storage based on the configurations that are defined in the VHD or VHDX files. Optionally, the VMs can be figured to access storage using pass through storage devices. Pass through storage devices are not defined in VHD or VHDX files; they are mapped directly to the Hyper-V servers. The devices can be physical disks that reside on Hyper-V servers or SAN (storage area network) LUNs (logical unit number) that are mapped to the Hyper-V servers.

The agent generates internal sessions the following types of VM backup jobs run:

• Mixed mode with the Allow file level restore option specified.
• Raw (full VM) mode with the Allow file level restore option specified.

However, when jobs of these types run, the agent does not access the VHD or VHDX files, which prevents the agent from generating internal sessions.