6.3.2. Creating a New RAID Device

To create a new RAID device, use the command in the following form as root:

mdadm --create raid_device --level=level --raid-devices=number component_device…

mdadm --create raid_device --level=level --raid-devices=number component_device…

This is the simplest way to create a RAID array. There are many more options that allow you to specify the number of spare devices, the block size of a stripe array, if the array has a write-intent bitmap, and much more. All these options can have a significant impact on the performance, but are beyond the scope of this document. For more detailed information, refer to the CREATE MODE section of the mdadm(8) manual page.

ls /dev/sd*

~]# ls /dev/sd*
/dev/sda  /dev/sda1  /dev/sdb  /dev/sdb1

mdadm --create /dev/md3 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1

~]# mdadm --create /dev/md3 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1
mdadm: array /dev/md3 started.