Latest revision as of 09:42, 22 April 2014

mdadm is a tool to create and manage software RAID. It allows you to

create a (new) software raid array. Think of two USB hard drives that you just bought and that you want to use in a RAID 1 configuration.
assemble an (existing) array. Think of two USB hard drives that you have in your shelve and that you have already made to a RAID array using the create command. When you re-attach them to your computer, you need to tell the computer how the disks belong together (RAID 0 or RAID 1 for example). That is what the assemble command is for.

Create

mdadm --create --verbose /dev/md0 --level=0 --raid-devices=2 /dev/sdh /dev/sdi

# mdadm --assemble --scan
mdadm: /dev/md/0 has been started with 2 drives.

You can store your mdadm configuration like this:

mdadm --detail --scan >/etc/mdadm.conf

Monitor your raid's status with the command

cat /proc/mdstat

@@ Line 1: / Line 1: @@
+mdadm is a tool to create and manage software RAID. It allows you to
+* '''create''' a (new) software raid array. Think of two USB hard drives that you just bought and that you want to use in a RAID 1 configuration.
+* '''assemble''' an (existing) array. Think of two USB hard drives that you have in your shelve and that you have already made to a RAID array using the ''create'' command. When you re-attach them to your computer, you need to tell the computer how the disks belong together (RAID 0 or RAID 1 for example). That is what the assemble command is for.
+= Create =
   mdadm --create --verbose /dev/md0 --level=0 --raid-devices=2 /dev/sdh /dev/sdi
+= Assemble =
+ # mdadm --assemble --scan
+ mdadm: /dev/md/0 has been started with 2 drives.
+= Store configuration =
+You can store your mdadm configuration like this:
+ mdadm --detail --scan >/etc/mdadm.conf
+= Monitor =
+Monitor your raid's status with the command
+ cat /proc/mdstat
+= See also =
+* [http://linux.die.net/man/8/mdadm mdadm's man page]
+* http://www.ducea.com/2009/03/08/mdadm-cheat-sheet/
+{{stub}}