Introduction

This blog shows the process of determining whether the virtual machine (VM) hardware version is compatible with various VMware products, including VMware ESXi, VMware Fusion, VMware Workstation, and so on. In addition, it discusses the potential issues users may encounter if the VM hardware version is incompatible.

The primary focus area is the VMware hardware version compatibility in relation to VMware ESXi product versions.

What is Type 1 Hypervisor

A Type 1 hypervisor, also known as a bare-metal hypervisor, is virtualization software installed directly on the computer hardware without requiring an underlying OS. It manages both the hardware and guest OS. 

Since it runs directly on the hardware, a bare-metal hypervisor provides better VM performance, along with greater scalability and availability.

What is VMware ESXi host and VM hardware version

VMware ESXi host

A VMware ESXi host is a physical server which runs VMware ESXi products, a bare-metal hypervisor enables the creation and management of VMs by directly interacting with hosts hardware. It provides a platform that allows you to run multiple VMs more efficiently. ESXi creates a logical pool of system resources such as memory, storage, networking, and processors, so that multiple VMs can share the same physical resources.

The following lists the crucial components related to an ESXi host:

·       VMkernal: It is the core of ESXi, which is responsible for managing all host components such as memory, storage, networking, and CPU.

·       Virtual Machines (VMs): It is a virtual environment that runs a guest OS on top of a hypervisor and each VMs has its own resources allocated by the ESXi host.

·       Datastores: It is a storage area that holds VM files and other data. It can be local or network-based storage.

·       Networking: ESXi includes virtual network components, such as vSwitches, which allows VMs to communicate with each other, or other ESXi hosts, and external networks.

VM hardware version

In ESXi, a virtual machine hardware version defines the available virtual hardware capabilities to VMs such as supported virtual CPU, memory, network adapter types, and some other components. In addition, it is important to check that a VNF-C (Virtual Network Function Component) uses the most up-to-date VM hardware version because different VM hardware versions support different components and different resources.

To determine whether to upgrade the VMs in an environment, you can review and compare hardware features available for different compatibility levels.

The following lists the key aspects of VM hardware version:

·       Compatibility: VM hardware version is compatible with specific versions of VMware ESXi host and running VMs on unsupported HW versions may lead to some critical issues, including not booting up the VMs properly or may not access certain features.

·       Features and Capabilities: Latest HW versions come up with new support and advanced features which can improve memory, networks, and so on.

·       Hardware Version Backward Compatibility: Newer versions of ESXi hosts support all the features from the older HW versions to ensure its compatibility.

ESXi Host and Compatible VM Hardware Versions

The following table shows the compatibility of ESXi host with different hardware versions:

Issues Encountered with Incompatible Versions

The following are some common issues users may encounter if VM hardware version is incompatible with the VMware ESXi host:

·       Unable to power ON the VM: VM may fail to power ON, displaying an error message indicating the compatibility issues.

·       Missing features: If the VM hardware version is outdated or incompatible, newer features introduced in later HW versions may be unavailable, affecting VM performance.

·       Unsupported Devices: If a VM is configured with virtual devices then the devices may not work properly if they are not supported by the ESXi host version, leading to performance issues or failures.

·       Snapshot and Backup Issues: If there is a compatibility issue, then certain snapshot and backup functionalities may not be available, limiting the ability to manage backups.

To resolve these issues, either upgrade or downgrade the ESXi host to a version that supports the VM HW version.

Common VMware Compatibility Issues and Recommendations

The following are some common types of compatibility issues that are observed if VM hardware version is not compatible with the VMware ESXi host:

·       Outdated Component Issue

Issue

Performance issues are observed if VM network devices or VMware tools are outdated; however, it is always recommended to use the correct VM hardware version in relation to the ESXi host version used.

Recommendation

Ensure that the VM hardware version is compatible with ESXi host version to overcome any performance degradations and keep the VMware tools up-to-date for better performance and security.

·       Snapshot Size Issue

Issue

If a VM runs with incompatible virtual hardware, it may continuously attempt to interact with the unsupported devices, leading to excessive log generations and errors. This can cause rapid snapshot size growth, impacting disk performance and slowing down disk I/O operations. As a result, snapshots may expand slowly but consume more storage space.

Recommendation

It is recommended that VMs hardware versions must be aligned with ESXi versions to ensure compatibility and prevent snapshot related issues. In addition, the snapshot size must be checked regularly and deleted if any compatibility issues are observed.

·       Central Processing Unit Issue

Issue

If VM hardware is incompatible, the ESXi host must manage unsupported features to compensate for hardware gaps. It must utilize more CPU that affects VMs, slowing down the processing speed that impacts performance, causing delays in applications response time.

Recommendation

It is recommended that VMs hardware versions must be aligned with ESXi versions to avoid CPU overhead and performance. Additionally, observe the CPU usage and utilization of the VMs with compatibility issues.

·       Storage Issue

Issue

If incompatibility in versions is observed, it leads to consuming more storage space to perform extra operations, including logging storage related errors or retries. As a result, the datastore fills up quickly, increasing the risk of data corruption, especially if the VM expects specific storage handling that the ESXi host cannot provide.

Recommendation

It is recommended that VMs hardware versions must be aligned with ESXi versions to avoid storage related issues. Additionally, if compatibility is suspected, it is recommended to regularly check for storage space and snapshot expansion.

Conclusion

By maintaining awareness of compatible VM hardware versions for each ESXi host, you can ensure smooth VM operations, better resource management, and the ability to leverage new VM features as VMware continues to enhance its virtualization platform.