Problem

The Linux CVM does not run out of memory and triggers OOM (Out of Memory) as shown below:

Common Cause

This issue may be caused by the min_free_kbytes configuration. It specifies the minimum idle memory of the Linux system (in kilobytes). When the system’s available memory goes below the set value of min_free_kbytes, the system will invoke oom-killer or forcibly restart depending on the vm.panic_on_oom kernel parameter:

• If vm.panic_on_oom=0 is set, the system prompts OOM and invokes oom-killer to kill the process using the most memory.
• If vm.panic_on_oom =1 is set, the system will restart automatically.

Solutions

1. Check the memory utilization and total number of processes as instructed in Steps.
2. Correct the min_free_kbytes configuration.

Steps

1. Check the memory utilization as instructed in High Memory Utilization. If the memory utilization is normal, proceed to the next step.
2. Check whether the number of processes exceeds the limit as instructed in Log Error “fork: Cannot allocate memory”. If not, proceed to the next step.
3. Log in to the CVM and run the following command to view the min_free_kbytes configuration.

   sysctl -a | grep min_free
   

   The min_free_kbytes value is in kbytes. For example, the min_free_kbytes = 1024000 shown below is 1 GB.
   
4. Run the following command to open the /etc/sysctl.conf configuration file with VIM editor.

   vim /etc/sysctl.conf
   

5. Press i to enter the edit mode and modify the vm.min_free_kbytes configuration item.

   Note：

   We recommend changing the vm.min_free_kbytes value to no more than 1% of the total memory.

6. Press Esc, enter :wq, and press Enter to save the configurations and exit the VIM editor.
7. Run the following command for the configuration to take effect.

   sysctl -p