In vSphere, what is a Hot Add?

Hot Add is a powerful feature in vSphere that allows you to enhance the resources allocated to a running virtual machine (VM) without requiring a reboot. Specifically, it enables the addition of memory or CPU resources dynamically while the VM is operational. This functionality is particularly valuable for environments that demand high availability and minimal downtime, as it allows workload adjustments to meet changing performance needs without interrupting services.

In scenarios where applications run on VMs and resource demands fluctuate, Hot Add provides the flexibility to scale resources on-the-fly. For example, during peak usage times, administrators can increase CPU cores or memory without disrupting user access or service continuity, thereby maintaining optimal performance.

The other options provided do not align with the definition of Hot Add. While adding new VMs without downtime is a general aspect of virtualization, it does not specify resource expansion for existing VMs. Migrating storage refers to moving VM storage from one location to another, which does not involve adding resources to the VM directly. Similarly, a backup solution pertains to data protection rather than resource allocation within a VM.