CentOS 6.5 Linux install raid 1 with efi firmware system

during the centos install.

make the two harddisk partition tables as below

sda (first drive)
- sda1 - FAT32 - /boot/efi - in firmware boot menu as "CentOS"
- sda2 - Linux software RAID - /boot
- sda3 - Linux software RAID - /

sdb (second drive)
- sdb1 - FAT32 - copy of /boot/efi - in firmware boot menu as "CentOS Backup"
- sdb2 - Linux software RAID - /boot
- sdb3 - Linux software RAID - /

example screen :

after the installation complete

do this commandsto make the secound harddisk bootable

# dd if=/dev/sda1 of=/dev/sdb1
# efibootmgr --create --disk /dev/sdb --label "CentOS Backup" --load "\\EFI\\redhat\\grub.efi"         

after that, update efi bios to boot the CentOS and CentOS Backup for the first and secound device in boot sequence.

Clonezilla for raid 1(mirror)

If you want to use clonezilla to clone a raid 1(mirror) to single drive.

You can try this as below:

In the GRUB menu,
select your preferred boot menu item and then hit tab,

add "dmraid=false" and then press enter.

or someone said

add nodmraid without quote is also work!

This way, your can imaging one of the drives.

Erase Disk with Linux DD Command

/dev/sda is the drive you want to erase. Please reconfirm the drive is correct or you will lost your data. Use it for your own risk!

Fill with zero like this

dd if=/dev/zero of=/dev/sda bs=1M

or Fill with random data like this

dd if=/dev/urandom of=/dev/sda bs=1M