The counter functionality in OpenVZ refers to the ability to track and monitor the usage of various system resources by each virtual private server (VPS) or container.
These resources can include CPU usage, memory usage, disk space, network bandwidth etc. The counter allows administrators to keep track of resource utilization and enforce limits, ensuring that each VPS only uses the resources allocated to it, preventing it from monopolizing shared resources and potentially causing a negative impact on other VPS hosted on the same physical server.
In essence, the counter functionality in OpenVZ is a crucial aspect of its resource management system.