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Common Issues with Hyper-V Backup

More often than not, Hyper-V backups make you face a whole new troubleshooting learning curve which guarantees consistent and reliable recovery points for virtual machines. But the good thing about them is that at least they help you solve the problems early on when Hyper-V backup issues arise.

Mostly, the reasons for the entire backup process failing are failures within the virtual machines. Continue reading for some of the most common issues of virtual machine backup and how to get past them.

· Freeing Up Disk Space

Each virtual machine has a minimum of 300GB of free space on VHD (virtual hard disk) and is backed up through host level backups. If the VSC (Volume Shadow Copy) process is to take place within the virtual machine and succeed, then this space is necessary. The host Hyper-V VSS (Microsoft Visual SourceSafe) writer has to request this call from inside the virtual machine. After the VSS process has been completed by the virtual machine, and to ensure that the consistent state of the virtual machine, the backup process is continued by the host by accessing the stateful data (sometime referred to as quiesced data). The entire process is bound to fail if the space is simply not available.

The simplest solution to this problem is to free up space on the virtual hard disk that is low on space by either expanding the virtual hard disk or by deleting some files.

· Integration Components

Installed within supported virtual machines, integration components are set agents that offer maxed out performance and straight interaction with the host server hypervisor. Their main purpose is to assist the operating system with shut down, disk input & output, network input & output performance enhancements, timekeeping, guest host data exchange and VSS assisted backups. Installation of the right integration components on all supported virtual machines is very important. Inconsistent backup operations pop up when the down level or mismatched components are installed.

To get past this issue, you need to use only the latest integration components. You also need to understand that the updates or the upgrades to your backup software might need integration components too on all VMs that are that are on a specific backed up host.

· No VSS Writers Available in the Virtual Machine

Sometimes it might happen that no matter what you do, the backups for a singular virtual machine will continue to fail. If you have already ascertained that it is not due to low disk space or running the wrong integration components, then you have to understand that the VSS writers on the virtual machine might be in corrupt or inconsistent state. To know for sure, you can run the command line “Vssadmin list writers” and if the command returns with absolutely no data then you definitely have this issue.

On the affected virtual machine, you need to restart the service “Hyper-V Volume Shadow Copy Requester” to solve this problem. After that, you can try running the command again. If the process is successful then should be able to see all the VSS writers. To know for sure, you can check the status of all the writers in the output where they will be labeled ‘OK’.

The overall point of Hyper-V backups and backing up all virtual machines is to protect your environment from disaster. To ensure that the process succeeds every time, you can use CloudBacko. The software helps you backup virtual machines with ease to unlimited cloud backup services. To get the software right now, or to know more about its features, you can visit