Introduction:
Welcome to this in-depth tutorial, where we will delve into the intricacies of Hyper-V virtualization, specifically focusing on the disparities between Generation 1 and Generation 2 virtual machines (VMs). Understanding these differences is crucial for making informed decisions when setting up and optimizing your virtual environment.
In earlier editions of Hyper-V starting with Windows Server 2008 and Windows Server 2012, virtual machines were limited to a single generation. However, starting with Windows 2012 R2 and subsequent releases( Windows Server 2016/2019/2022), users gained the flexibility to opt for an additional choice: generation 2 when setting up virtual machines.
As per Microsoft, generation 2 virtual machines feature a streamlined virtual hardware model, potentially leading to enhanced boot and installation times compared to their generation 1 counterparts.
Generation 1 VMs: A Legacy Approach
- BIOS Configuration:
Generation 1 VMs operate on the traditional BIOS-based architecture, where a digital BIOS is emulated by Hyper-V to initialize virtual hardware. This legacy approach ensures compatibility with older systems and operating environments. - IDE Virtual Disks:
In Generation 1, VMs rely on a virtual IDE controller for booting from IDE virtual disks. Recognizing virtual SCSI controllers necessitates the installation of Hyper-V Integration Services on the guest operating system, adding an extra layer of configuration. - Emulated Hardware:
Generation 1 VMs emulate essential hardware components, including a legacy network adapter, virtual floppy drive, and virtual COM ports. This emulation mimics real hardware behavior, ensuring compatibility with a wide range of operating systems. - Hardware Limits:
While effective, Generation 1 VMs come with specific hardware limitations, such as support for 2 IDE controllers, a maximum of 4 SCSI controllers, and adherence to a 2TB disk limit with MBR partitioning.
Generation 2 VMs: Modern Advancements
- UEFI BIOS Support, GPT, and Secure Boot:
Generation 2 VMs usher in modern advancements with support for the Unified Extensible Firmware Interface (UEFI) BIOS. This brings benefits like GPT partitioning, overcoming the 2TB disk limit, and enhanced security through Secure Boot. - Boot Enhancements:
Unlike Generation 1 VMs, Generation 2 VMs can boot from SCSI virtual disks, providing more flexibility in storage configurations. Native VMBUS support for synthetic hardware during VM boot further streamlines the process. - PXE Boot Option:
Generation 2 VMs simplify the PXE boot process with a synthetic network adapter. This improvement eliminates manual operations required for PXE boot in Generation 1 VMs, enhancing overall usability. - VHDX Virtual Disks:
Exclusive support for VHDX virtual disk format is a notable feature of Generation 2 VMs. This format offers advantages such as improved alignment, larger disk size limits, better resistance against power loss, and overall enhanced performance. - Other Advantages:
Generation 2 VMs boast faster boot times, with a 20% improvement, and quicker guest operating system installations, taking up to 50% less time. With synthetic hardware usage, there are fewer devices, potentially increasing overall VM performance.
Requirements and Advantages
- Requirements for Generation 2 VMs:
To harness the benefits of Generation 2 VMs, ensure your Hyper-V host is running on Windows Server 2012 R2 and later Windows Server 2016 / Windows Server 2019 / Windows Server 2022 . Or if you are running a client OS , then Windows 8.1 and later ( Windows 10 / Windows 11 ) . Additionally, guest operating systems should be 64-bit versions of Windows Server or Windows 8 and later. ( Note : Make Sure to check the Supported Operating System below in this article for each generation as there is difference between 32-bit guests and 64-bit guests) - Advantages of Using Generation 2 VMs:
Generation 2 VMs offer a myriad of advantages, including improved performance, enhanced security, more reliable VHDX virtual disks, and higher hardware limits. These make them the preferred choice for modern 64-bit operating systems.
Gen 1 and Gen 2 VMs Use Cases
Use Case |
Gen 1 VMs | Gen 2 VMs |
Compatibility | More suitable for executing older software applications or 32-bit guest operating systems. | Might lack compatibility with older software applications or 32-bit guest operating systems. |
Device Support | Provides support for a restricted set of virtual devices and may not have the capability to utilize larger virtual hard disks or advanced boot options such as Secure Boot. | Provides compatibility with a greater number of virtual devices and has the capability to utilize larger virtual hard disks or advanced boot options, such as Secure Boot. |
Boot Time | Delayed boot times attributed to the utilization of legacy BIOS firmware in Generation 1 VMs. | Quicker startup periods owing to the adoption of the Unified Extensible Firmware Interface (UEFI) firmware in Generation 2 VMs. |
Integration | Restricted integration services, including limited support for online backups or remote desktop functionality. | Enhanced integration services, including the provision of support for online backups or remote desktop, are accessible. |
Security | Restricted security capabilities, including the absence of support for Secure Boot. | Advanced security functionalities, such as Secure Boot support, shielded VMs, and virtual TPM, are accessible. |
Migration | Restricted migration possibilities, as Generation 1 VMs cannot be transformed into Generation 2 VMs. | Transitioning from Generation 1 VMs to Generation 2 VMs is feasible but necessitates the creation of a new VM and the manual migration of data and settings. |
OS Support | Provides compatibility with an extensive array of guest operating systems, encompassing older editions of both Windows and Linux. | Compatible with the latest versions of Windows and Linux, though older operating systems may not be supported. |
Hardware Support | Operates on a diverse range of hardware, including outdated processors and CPUs lacking virtualization capabilities. | Necessitates modern hardware, including a 64-bit processor with second-level address translation (SLAT) support, virtualization extensions (Intel VT or AMD-V), and compatibility with UEFI firmware. |
Performance | Might not leverage the most recent hardware enhancements and virtualization features, resulting in diminished performance. |
Capable of harnessing the latest hardware advancements and virtualization features, resulting in enhanced performance. |
Which guest operating systems are supported?
The table below illustrates the 64-bit versions of Windows compatible for use as a guest operating system in both generation 1 and generation 2 virtual machines.
64-bit versions of Windows | Generation 1 | Generation 2 |
---|---|---|
Windows Server 2022 | ✔ | ✔ |
Windows Server 2019 | ✔ | ✔ |
Windows Server 2016 | ✔ | ✔ |
Windows Server 2012 R2 | ✔ | ✔ |
Windows Server 2012 | ✔ | ✔ |
Windows Server 2008 R2 | ✔ | ✖ |
Windows Server 2008 | ✔ | ✖ |
Windows 11 | ✖ | ✔ |
Windows 10 | ✔ | ✔ |
Windows 8.1 | ✔ | ✔ |
Windows 8 | ✔ | ✔ |
Windows 7 | ✔ | ✖ |
The table below outlines the 32-bit versions of Windows that are compatible for use as a guest operating system in both generation 1 and generation 2 virtual machines.
32-bit versions of Windows | Generation 1 | Generation 2 |
---|---|---|
Windows 10 | ✔ | ✖ |
Windows 8.1 | ✔ | ✖ |
Windows 8 | ✔ | ✖ |
Windows 7 | ✔ | ✖ |
The table below indicates the Red Hat Enterprise Linux (RHEL) and CentOS versions suitable for use as guest operating systems in both generation 1 and generation 2 virtual machines.
Operating system versions | Generation 1 | Generation 2 |
---|---|---|
RHEL/CentOS 8.x series | ✔ | ✔ |
RHEL/CentOS 7.x series | ✔ | ✔ |
RHEL/CentOS 6.x series | ✔ | ✔ Note: Only supported on Windows Server 2016 and above. |
RHEL/CentOS 5.x series | ✔ | ✖ |
The table below displays the Debian versions compatible for use as a guest operating system in both generation 1 and generation 2 virtual machines.
Operating system versions | Generation 1 | Generation 2 |
---|---|---|
Debian 10.x (buster) series | ✔ | ✔ |
Debian 9.x (stretch) series | ✔ | ✔ |
Debian 8.x (jessie) series | ✔ | ✔ |
Debian 7.x (wheezy) series | ✔ | ✖ |
The table below outlines the FreeBSD versions that are suitable for use as a guest operating system in both generation 1 and generation 2 virtual machines.
Operating system versions | Generation 1 | Generation 2 |
---|---|---|
FreeBSD 12 to 12.1 | ✔ | ✔ |
FreeBSD 11.1 to 11.3 | ✔ | ✔ |
FreeBSD 11 | ✔ | ✖ |
FreeBSD 10 to 10.3 | ✔ | ✖ |
FreeBSD 9.1 and 9.3 | ✔ | ✖ |
FreeBSD 8.4 | ✔ | ✖ |
The table below provides information on the versions of the Red Hat Compatible Kernel Series suitable for use as a guest operating system in both generation 1 and generation 2 virtual machines.
Red Hat Compatible Kernel Series versions | Generation 1 | Generation 2 |
---|---|---|
Oracle Linux 8.x series | ✔ | ✔ |
Oracle Linux 7.x series | ✔ | ✔ |
Oracle Linux 6.x series | ✔ | ✖ |
The table below illustrates the versions of the Unbreakable Enterprise Kernel that are compatible for use as a guest operating system in both generation 1 and generation 2 virtual machines.
Unbreakable Enterprise Kernel (UEK) versions | Generation 1 | Generation 2 |
---|---|---|
Oracle Linux UEK R3 QU3 | ✔ | ✖ |
Oracle Linux UEK R3 QU2 | ✔ | ✖ |
Oracle Linux UEK R3 QU1 | ✔ | ✖ |
The table below outlines the versions of SUSE that are suitable for use as a guest operating system in both generation 1 and generation 2 virtual machines.
Operating system versions | Generation 1 | Generation 2 |
---|---|---|
SUSE Linux Enterprise Server 15 series | ✔ | ✔ |
SUSE Linux Enterprise Server 12 series | ✔ | ✔ |
SUSE Linux Enterprise Server 11 series | ✔ | ✖ |
Open SUSE 12.3 | ✔ | ✖ |
The table below indicates the versions of Ubuntu that are compatible for use as a guest operating system in both generation 1 and generation 2 virtual machines.
Operating system versions | Generation 1 | Generation 2 |
---|---|---|
Ubuntu 20.04 | ✔ | ✔ |
Ubuntu 18.04 | ✔ | ✔ |
Ubuntu 16.04 | ✔ | ✔ |
Ubuntu 14.04 | ✔ | ✔ |
Ubuntu 12.04 | ✔ | ✖ |
Q&A:
- Is it feasible to transform a Generation 1 VM into a Generation 2 VM?
No, the conversion of a Generation 1 VM to a Generation 2 VM is not supported. To migrate to a Generation 2 VM, the recommended approach is to create a new instance and manually transfer your data and configurations. - Can both Generation 1 and Generation 2 VMs coexist on the same host server?
Certainly, it is feasible to run both Generation 1 and Generation 2 VMs on a single host server, provided the server aligns with the hardware prerequisites for both types of VMs. - Is there a cost disparity between Generation 1 and Generation 2 VMs?
No, there is no financial distinction between Generation 1 and Generation 2 VMs. Both variations are inclusive with the relevant editions of Windows Server, ensuring cost parity between the two.
Exceptions and Conclusion
- Exceptions
Despite the advancements, there are scenarios where Generation 1 VMs might be preferable. For instance, running 32-bit operating systems, using older OS versions without UEFI support, or requiring compatibility with specific hardware features like COM ports and virtual floppy disks. - Conclusion:
In conclusion, the choice between Generation 1 and Generation 2 VMs depends on your specific use case and compatibility requirements. While Generation 2 VMs are recommended for their modern features, careful consideration should be given to the unique needs of your virtualized environment.
By thoroughly understanding the nuances outlined in this guide, you’ll be better equipped to make informed decisions and optimize your Hyper-V virtualization setup.