Configure and Customize Dell PowerFlex v3.6.x

Check cstate Settings and Change the GRUB template for CentOS, SLES and Red Hat

Using C-States help to optimize or reduce power consumption in idle mode. Change the GRUB template on every node to ensure that the CPUs maintain good performance in terms of latency. These changes apply to Storage-Only nodes only, no need to modify these settings for SVMs or Virtual Machines

1. Check current cstate value:

   cat /sys/module/intel_idle/parameters/max_cstate
   

   The accepted values are 1 or 0. Change the settings for any other values.

   NOTE:If the cstate value displayed is 1 or 0, skip the remaining steps.
2. To change the cstate settings in GRUB for the running kernel. Open the GRUB template for editing:

   vi /etc/default/grub
   

3. Find the GRUB_CMDLINE_LINUX= line configuration option and append the following to the line:

   intel_idle.max_cstate=0 processor.max_cstate=1 intel_pstate=disable

   Example:

   GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=rhel/root 
   rd.lvm.lv=rhel/swap rhgb intel_idle.max_cstate=0 processor.max_cstate=1 intel_pstate=disable quiet"

4. Regenerate the new GRUB:
   for BIOS

   grub2-mkconfig -o /boot/grub2/grub.cfg

   or for EFI/centos

   grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg

   or for EFI/redhat

   grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg

   or for EFI/sles

   grub2-mkconfig -o /boot/efi/EFI/sles/grub.cfg

5. Regenerate the initrd:

   dracut -f

6. Stop and then disable tuned:

   systemctl stop tuned
   systemctl disable tuned

7. Place the node into maintenance mode.
8. Run reboot to reboot the node.
9. Ping the node to ensure that the GRUB change is implemented.
   The ping time should be in the 0.03 millisecond range.
10. Repeat the procedure on every node to ensure that the CPUs maintain good performance in terms of latency