In OpenVZ, you can use the vztop utility to monitor system resources in real time. When executed, the utility displays information about processor, swap and memory usage, number of tasks, load average, and uptime at the top of the screen. You can change the default meters by pressing F2 or S. For example, you can run the following command on the server to view your current system resources:
# vztop
1 [ 0.0%] Tasks: 77, 65 thr; 1 running
2 [||| 2.6%] Load average: 0.02 0.03 0.05
3 [|||| 4.6%] Uptime: 06:46:48
4 [| 0.7%]
Mem[||||||||||||||||||||| 344M/3.68G]
Swp[ 0K/3.87G]
The numbers on the left represent the number of CPUs/cores in the system. The progress bar shows their load and can be comprised of different colors. By default, the CPU progress bar is displayed in four colors:
- blue - low priority processes,
- green - normal priority (user) processes,
- red - kernel processes,
- cyan - virtualization time.
The memory progress bar is comprised of three colors:
- green - used memory pages,
- blue - buffer pages,
- yellow/orange - cache pages.
The swap progress bar include only one color—red—which denotes used swap space.
The command output is updated in intervals set with the -d option in tenths of a second. If the -d option is omitted, the default interval is 1 second (i.e. -d 10).
