Can I split one RAID1 partition in two?

Question

I have a linux box with CentOS 6.2 and a RAID1 (2x 2Tb) configuration:

/dev/md1 -> / (10G)
/dev/md2 -> /home (1.9T)

I want to split the md2 in two different partitions, so I can get the following configuration:

/dev/md1 -> / (10G)
/dev/md2 -> /home (1T)
/dev/md3 -> /example (900G)

How can I achieve this? I already know that I can resize the partition, but that doesn't alter the real partition table (only the md device), so how can I do this?

Answer 1

If you are not using LVM, you need to:

• remove the md device (using mdadm),
• remove the partition (using fdisk),
• recreate the needed partitions (using fdisk),
• and then recreate the md device (using mdadm).

Answer 2

you are best of using logical volumes.

You can then create, expand and pretty much do as much as you want.

there is a nice guide here

http://www.gagme.com/greg/linux/raid-lvm.php