Other Information
Before configuring the VM memory hotplug feature, learn the specifications, supported version, license requirement, constraints, and application scenarios of this feature.
Specifications
In the XML configuration file of a VM, a maximum of one NUMA node whose initial memory is 0 is supported.
Availability
- Supported version: Only libvirt 6.2.0 and QEMU 6.2.0 are supported.
- License requirement: none.
Constraints
- OS
- VM specification
Among the NUMA nodes configured for a VM, a maximum of one NUMA node whose initial memory is 0 is supported.
- Hotplug specification
The VM XML configuration file must contain the maxMemory node as required by QEMU. This node specifies the number of memory slots (setting the slots attributes) dedicated for VM's memory hotplug and the maximum total memory that can be achieved through hotplug (setting the value of maxMemory).
In addition to the constraints in the VM XML configuration file, some configuration parameters in physical machines also put constraints on the maximum number of hotplug operations on the corresponding VMs and the maximum memory capacity provided by memory hotplug. The specific constraints depend on the OS type.
Application Scenarios
In large-scale VMs and centralized management scenarios, especially on cloud computing platforms, NUMA nodes that are temporarily allocated with 0 memory are often reserved in VMs in advance, aiming to efficiently manage large-scale VMs. This method ensures that memory resources can be quickly increased and allocated when more memory is required, facilitating dynamic memory expansion.