Monitoring load Linux server using a utility atop

Atop – Advanced Performance Monitor for Linux and FreeBSD. In fact – this is an analogue built-in utility top, but with more features. Enables you to monitor CPU usage, memory, disk, network, etc.
Installing atop for Centos:
# Yum install atop

Run the program:
# Atop

You can change the appearance using hotkeys. The most commonly used:
m – sorting processes used memory;
d – by use of the disk;
n – the use of the network (only available with patch);
v – show more detailed information about processes;
i – change time checking (default 10 seconds);
g – restores the default settings.

Default atop writes logs approximately every 10 minutes in the folder / var / log / atop.
You can view the log for a specific date command:
20140911 # atop -r -b 13:00

Here we specify the date and time, respectively. After opening the log, you can scroll back and forth every 10 minutes, use t and T.