Nice tutorial on Linux kernel.
vm.min_free_kbytes setting allows kernel to compute a minimum value in the low memmory zone and reserve it for its own use.
To read the current value
[Fri Mar 24 15:18:05 root@system:~]$sysctl vm.min_free_kbytes
vm.min_free_kbytes = 1888
To set new value of 4MB. Based on your system requirement configure the value. Ideally 1.8% is good enough.
echo 4096 > /proc/sys/vm/min_free_kbytes
To configure permenantly on every reboot add the below entry to /etc/sysctl.conf
Some basics on Linux Software RAID. There are good references on the same in the same wiki.
This article provides the steps to boot to single user mode and reset the root password.
Source: LayerStack Tutorials – LayerStack – Resetting root password by booting into Single User Mode from Linux GRUB
A short description of how to enable root login over SSH in Linux.
Source: 5.2.2. Enable root login over SSH Red Hat Enterprise Linux 6 | Red Hat Customer Portal
A simple article on how to load 100% CPU load in Linux.
First step is to identify the number of cores.
Run the command “yes > /dev/null &” for N times. N denotes the number of processors identified via “cat /proc/cpuinfo” command. 2N is one better number.
MOK Architecture. The keys added via mokutil via any Linux OS, will be stored in the MOK database. Since its a boot service variable, it will be stored in the BIOS NVRAM. On next boot the shim layer will prompt for enrolling the key. Once enrolled the key can be used to validate the respective async drivers (not part of OS distribution) by kernel to allow installing them during OS boot or run time.
Source: Machine Owner Key (MOK) – Understanding the UEFI Secure Boot Chain