ESXi Hypervisor is the abstraction layer that enables running of different virtual machines sharing the same physical hardware resources. VMware ESXi 6.5 has significant scalability enhancements. Let's compare and contrast the scalability improvements since ESXi 5.5:
| Feature | vSphere 5.5 | vSphere 6.0 | vSphere 6.5 |
| Logical processors (CPUs) | 320 | 480 | 576 |
| Physical memory | 4 TB | 6 TB – 12 TB | 12 TB |
| NUMA nodes | 16 | 16 | 16 |
| vCPUs | 4,096 | 4,096 | 4,096 |
| Storage LUNs per host | 256 | 256 | 512 |
| VMFS datastore per host | 256 | 256 | 512 |
| Virtual machines per host | 512 | 1,024 | 1,024 |
Refer to the VMware vSphere 6.5 Configuration Maximums guide for more information regarding the scalability maximums at https://www.vmware.com/pdf/vsphere6/r65/vsphere-65-configuration-maximums.pdf.
A brief insight into all the new features made available with vSphere 6.5 has been put together in the VMware's technical whitepaper What's New in VMware vSphere® 6.5 at http://bit.ly/vSphere65WhatsNew. Although I have shortened the URL for your benefit, you can always Google for the title text to find this whitepaper.
As the whitepaper introduces the components pretty neatly, we will not be doing the same in this book. This book will introduce you to the new changes in the respective chapters.