One of the features of OpenVZ is that it allows you to manage the memory allocation to the containers on a very fine-tuned level and allows you to fully control memory resources on the node.
You can use vzmemcheck to check the amount of memory that is currently being used by the server and also by each individual container. Using vzmemcheck on its own will give you the memory usage that is currently being used by the entire server. This is shown in the following screenshot:
In the previous example, we used the vzmemcheck command with no options or flags to display the current memory that is being used by the server.