A few virtual machines are present which include domain controller and terminal server. It is necessary to halt the virtual machines before backing them up.



Is it feasible to use the integrated Windows Server archiving tool to backup virtual machines internally without stopping the server?

Virtual machines are just like regular machines with regards to data backup and recovery. Both internal and external methods can be utilized to back them up.

Considering the ease of snapshotting virtual machines, or at the very least backing up their disks (in the case of Hyper-V, vhd files), it is a viable option for quick and simple data archiving. By creating snapshots, one can save the machine's state and configuration in a single file while allowing continued machine operation. In addition, backing up virtual machine disks allows for fast and efficient data recovery in case of system failure.

May I ask which hypervisor you are currently employing?
Typically, the virtual machine does not need to be stopped to carry out a backup. Instead, one can create a snapshot and back up the snapshot file. This is the usual process for most virtual machine backup software.

However, in some cases, snapshots cannot be relied upon as the contents might not be consistent, risking data loss upon restoration. In instances such as a running database virtual machine, backing up with the database and not the hypervisor is necessary. Essentially, the hypervisor must match the database in use. Only some file dumps or application servers with unvarying installed applications may utilize snapshot backups.

Yes, it is possible to back up virtual machines without stopping them. In fact, this is necessary for domain controllers as Windows Backup creates system state backups that are vital for restoring AD data.

Moreover, Windows Server Backup also serves to keep database logs from becoming oversized while in operation. Such databases include jet, MS SQL, exchange, and so on. Not only does it aid in preventing bloating logs, but also in maintaining efficient server performance.

Backups of virtual machines can be executed at the host level through a virtualization layer that traditional backup products may not recognize, leading to faster data copying from VMs. In general, these backup products combine entire virtual machine copying and restoration of specific files/application objects.

Preservation of application data is just as significant, if not more so, than file data for system administrators today. Applications such as Microsoft SQL Server, Exchange Server, and Active Directory have complex data structures not always accounted for during a backup. As a result, several backup products operate at both the internal and file system level to ensure correct copying. The Volume Shadow Copy (VSS) mechanism is often used in virtual environments to create backups at the application level.

The reliability of such mechanisms is crucial for protecting data and, therefore, most backup products feature their own implementations of integration mechanisms such as the Windows VSS. Host-level backups leverage virtual environment capabilities with functions like Changed Block Tracking for faster backup speeds compared to traditional products. These backups reduce downtime, RPO, and RTO by working with specialized virtual environment interfaces and isolating the VM from specific server hardware.

The scenario you've presented, involving the backup of virtual machines without halting the server, requires careful consideration of various technical aspects.
The integrated Windows Server archiving tool, while capable of performing basic file-level backups, may not be the ideal solution for creating consistent backups of running virtual machines. This is primarily due to the complexities involved in capturing the state of a live virtual machine without impacting its integrity and performance.

When it comes to live backups of virtual machines, several challenges need to be addressed. One critical concern is maintaining data consistency during the backup process. Unlike traditional file backups, capturing the state of a virtual machine's disks while applications and services are actively running requires sophisticated mechanisms to ensure that the backed-up data reflects a coherent point-in-time state.

The impact on system resources and performance must be carefully managed when conducting live backups. While snapshot-based backup methods are commonly used to create live backups, they can lead to issues such as disk space overutilization, increased I/O load, and potential performance degradation if not properly handled.

Given these considerations, my recommendation would be to leverage specialized backup solutions designed explicitly for virtualized environments. These enterprise-grade backup tools offer advanced features tailored to virtual machine backups, such as the ability to create application-consistent backups, support for live snapshots, and integration with hypervisor APIs for efficient capture of virtual machine states.

By implementing a dedicated virtualization-aware backup solution, organizations can ensure the reliability and integrity of their backup data while minimizing the impact on production systems. Such solutions often provide centralized management interfaces, scheduling options, and support for various virtualization platforms, allowing for a more comprehensive and efficient approach to virtual machine backups.