If you are using a LUN to boot from SAN, you need to ensure the changes in your configuration files are applied upon rebooting. This is done by rebuilding the initial ramdisk (initrd or initramfs) to include the proper kernel modules, files and configuration directives after the configuration changes have been made. As the procedure slightly varies depending on the host, we recommend that you refer to your vendor's documentation for the proper procedure.
lsinitrd /boot/initramfs-$(uname -r).img | grep dmAn example file that may be missing that could result in failure to boot:
...(kernel build)/kernel/drivers/md/dm-round-robin.koWhen rebuilding the initial ramdisk, you need to confirm that the necessary dependencies are in place before rebooting the host to avoid any errors during boot. Refer to your vendor's documentation for specific commands to confirm this information.