Configuring memory for virtual machines

You can configure the amount of memory that can be provisioned for virtual machines by setting the RAM overcommitment ratio. This is the ratio of the amount of maximum reserved RAM to physical. The default ratio is 1, which means that you cannot provision more than the amount of physical RAM available on all of the compute nodes. By increasing the ratio, you can increase the number of virtual machines running in the compute cluster at the cost of reducing their performance. The maximum recommended RAM overcommitment ratio is 1.5.

Memory overcommitment for virtual machines is only available if all of the compute nodes have enough swap space. Before enabling RAM overcommitment, you need to calculate the required swap space, and then configure it on each compute node.