raid-disk 0

device /dev/sdb3

raid-disk 1

 

raiddev /dev/md2

raid-level 1

nr-raid-disks 2

chunk-size 64k

persistent-superblock 1

device /dev/sda5

raid-disk 0

device /dev/sdb5

raid-disk 1

 

# raidhotadd /dev/md0 /dev/sdb2

# raidhotadd /dev/md1 /dev/sdb3

# raidhotadd /dev/md2 /dev/sdb5

 

# more /proc/mdstat

to see the sync process.

 

5. Installing GRUB for the original hard disk, the step is the same as the command above-mentioned.

Now, you can exchange the two hard disk to boot system, the everything is the same, you got a raid-1 mirrored whole system, not only data partition, but also system root partition.

===================

 

Part II - New installation for Redhat Linux 7.3

 

If you have two same hard disk to install Redhat Linux, you can make a root raid-1 mirrored system while installation. There is no many articles mention about it, but it is possible and very easy to do. The following is steps.

 

1. partition

 

When you install a new system with Redhat Linux 7.3, you must use fdisk to make partition manually, the same word, making them exact same. And /dev/sda2 /dev/sda3 /dev/sda5 use Raid Auto-Detection 'fd', the same for /dev/sdb2 /dev/sdb3 and /dev/sdb5.

 

Back to GUI interface, select 'make raid', make /dev/sda2 and /dev/sdb2 as /boot, /dev/sda3 and /dev/sdb3 as swap, /dev/sda5 and /dev/sdb5 as / respectively. Finally, click 'ok' to continue to install system.

 

After installation finished, reboot system and run

# dd if=/dev/sda of=/dev/sdb bs=512 count=1

 

So now, you get a raid-1 mirrored system, the two hard disk can be exchanged. Both of them are bootable.