A VM snapshot preserves the state and data of a VM at a specific point in time, making it popular as a quick failsafe measure. In VMware vSphere environment, you can create VM snapshots in 2 ways:

Quiesced virtual machine snapshot ensures that the guest file system is in a file-system and application consistent state for backup purposes. It can avoid inconsistent issue of SQL Server, Active Directory, and other applications.

Sometimes you may find yourself failed to quiesce the virtual machine, for example, cannot take a quiesced snapshot of Windows 2008 R2 virtual machine. In this article, I will analyze the reason why this error happens and how to fix failed to quiesce the virtual machine snapshot error.

If an error occurred while quiescing the virtual machine “Failed to quiesce the virtual machine” while creating a quiesced snapshot or cloning your VM, there are plenty of reasons that can cause you unable to quiesce guest file system during snapshot creation. For example:

In this article, I will introduce how to troubleshoot and fix the error Failed to quiesce the virtual machine snapshot.

Since there are many reasons that can cause the “Failed to quiesce the virtual machine” error, the ways to solve it varies. In this section, I will introduce how to fix this error in different situations.

Before all of this, you need to perform the standard troubleshooting process, referring to VMware’s official documentation: Troubleshooting Volume Shadow Copy (VSS) quiesce related issues (1007696)

VMware Tools is required if you want to enjoy the ability to take quiesced snapshots of the guest operating system, the enhanced graphics, and mouse performance, or the better memory management, etc. It is a set of services and modules that enable several features in VMware products for better management of, and seamless user interactions with, guests operating systems.

Therefore, if you are unable to quiesce guest file system during snapshot creation, it is possible that the VMware Tools on your guest machine is outdated or accidentally deleted.

If so, you can reinstall VMware Tools on virtual machine or update it to fix this problem.

For example, follow the following steps manually update the VMware Tools on ESXi host:

1. Download the latest VMware Tools package from the official website.

2. Access to the ESXi host, extract the content of the package and transfer the VMware Tools files to the folder where the VMware Tools are stored on ESXi.

For example, on ESXi 6.5, the VMware Tools files are located under /vmimages/tools-isoimages or /productlocker.

3. Verify if ESXi does replaced the old VMware Tools files with new files and if you have successfully updated VMware Tools on ESXi host. And then you can upgrade the VMware Tools on your specific guest VMs.

If you are unable to quiesce guest file system during snapshot creation and the error reports:

"Cannot create a quiesced snapshot because the snapshot operation exceeded the time limit for holding off I/O in the frozen virtual machine"

This occurs when you try to create a quiesced snapshot on a VM that does not have free space, or the I/O in the VM is high and the quiescing operation is unable to flush all the data to disk, while further I/O is created.

To solve this issue, try the following steps after troubleshooting:

1. Make sure that all virtual machine drives have enough free space.

2. Reduce the amount of ongoing I/O to the virtual machine.

If you cannot take a quiesced snapshot of Windows 2008 R2 virtual machine, and received the Volume Shadow Copy Service error: Unexpected error calling routine IOCTL_DISK_SET_SNAPSHOT_INFO(\\.\PHYSICALDRIVE1) fails with winerror 1168. hr = 0x80070490, Element not found.

This issue occurs because the VM has a GPT disk without an MSR (Microsoft Reserved) partition. VMware Snapshot Provider works under Microsoft VSS framework. The Microsoft VSS framework will send the IOCTL IOCTL_DISK_SET_SNAPSHOT_INFO to the disks. If the disk is a GPT disk without a MSR partition, the IOCTL would fail and whole VSS process fails.

To solve this issue, you can add a new GPT disk with an MSR, and migrate the data to the new disk, or shrink the volume by the default MSR size of 32MB or 128MB.

Although convenient as a quick failsafe, VM snapshot is still an unstable feature that may affect your VM performance and cannot be used as an independent backup method for restoration. Therefore, backup is still a necessary way of VM protection for enterprise. You can choose to use snapshot or backup depending on your needs.

For enterprise - level backups, it requires more efficient backups, you can only use a professional backup software to complete. So, you can try AOMEI Cyber Backup, the free virtual machine backup solution. It’s specialized in backup, support both paid and free versions of VMware ESXi, and can create backups for virtual machines at the same time and schedule automatic backup tasks, monitors the status and sends email notifications if there's an error, as well as guarantee data security during backup and recovery.

*You can choose to install this VM backup software on either Windows or Linux system.

Easy and secure procedures to create a perfect backup task

Before you start, you need to Bind Devices first: Access to AOMEI Cyber Backup web client, navigate to Source Device > VMware > + Add VMware Device to Add vCenter or Standalone ESXi host. And then click … > Bind Device.

1. Click Backup Task >> Create New Task to automate a new VM backup.

2. In the opened window, enter task name first and select VMware ESXi device and the virtual machines. Then select a location to store backup files.

3. In Schedule page, set up automatic backup task with different strategies.

4. (Optional) Set up Backup Cleanup policy that helps to delete unwanted backup files which saves storage space. Note this function is available in Premium Edition.

3. Click Start Backup. You can monitor the backup status from the main screen.

The scheduled backup task will run VM backups automatically, and the backup files can be stored in local or network location and they are independent and secure from each other.

It is more convenient and safer to utilize a professional tool to protect your virtual machines. Regular backups allow you to restore entire VM easily and fast without worrying about errors.

In this article, I summarized reasons that may cause you failed to quiesce the virtual machine snapshot, and briefly introduced 2 resolutions to solve this issue. But if you want a stable data protection insurance, VM backup may meet your needs better.