This tunable exists if you have initrd support compiled in the kernel. In that case, the "real" root device can be changed from within linuxrc by writing the number of the new root filesystem device to this file, e.g.:
# echo 0x301 > /proc/sys/kernel/real-root-dev
Except where otherwise stated, original content is © 2003-2017 LinuxInsight. Linux® is the registered trademark of Linus Torvalds in the U.S. and other countries. Drupal® is a registered trademark of Dries Buytaert. Other marks are property of their respective owners. Comments are property and responsibility of their authors.