Question

How to check what process loads CPU, memory and other system resources in a period of time using atop utility?

Answer

1. Install atop and screen packages:

   In RHEL/CentOS:

   # yum install epel-release
   
   # yum install screen atop 
   
   

   In Debian/Ubuntu:

   # apt-get install screen atop
   

2. Run screen command. This will allow to keep atop process running if SSH session is disconnected:

   # screen
   

3. Inside screen session, run a command atop with desired parameters, for example, to write information regarding system state in log file /root/atop.log every 10 seconds for 17280 times (48 hours of logging):

   # atop -w /root/atop.log 10 17280
   

4. After 48 hours passed, you may read what happened with the server using a command:

   # atop -r /root/atop.log
   

   A hotkey t will jump one interval forward. Shift+T will jump one interval backward.