Memory overcommitment is used to control the virtual memory capacity allocated to VM instances. The calculation formula is as follows: Virtual memory capacity can be allocated = Physical memory capacity x Memory overcommitment ratio.
- Assume that the physical memory is 128 GB. If the memory overcommitment ratio in the global settings is set to 2, the memory that can be allocated to VM instances is 256 GB.
- Excessively large memory overcommitment ratio might seriously affect the host memory performance and cause the out of memory (OOM) condition. Therefore, memory overcommitting is not recommended. If you do need to perform memory overcommitting, make sure that the overcommitment ratio does not exceed 1.2.