Kernel Tuning

General Information

Kernel tuning using sysctl.conf

Checklist

• Any distro, but many examples are done via Red Hat based systems

Problem: Unable to access a VM's console, and it shows out of memory errors on boot.

Solution: Reduce the value of “vm.nr_hugepages” to less than 1/2 of total memory in MBs.

/etc/sysctl.conf

vm.nr_hugepages = 1024

1 hugepage = 2 MBs, so the above is equal to 2GB

Explanation: Hugepages that is configured to be greater than or equal to total installed memory causes memory starvation during boot due to no memory available for normal use.

Alternative config location: Hugepages could also be configured at /boot/grub/grub.conf

TODO: VM Swappiness content will go here.