Creating A Complex Raid 10 With Mdadm; Understanding The Mdadm Raid10 - Novell LINUX ENTERPRISE SERVER 10 SP2 - STORAGE ADMINISTRATION GUIDE 05-15-2009 Administration Manual

The procedure in this section uses the device names shown in the following table. Make sure to
modify the device names with the names of your own devices.
Scenario for Creating a RAID 10 (0+1) by Nesting
Table 7-4
Raw Devices
/dev/sdb1
/dev/sdc1
/dev/sdd1
/dev/sde1
1 Open a terminal console, then log in as the root user or equivalent.
2 Create 2 software RAID 0 devices, using two different devices for each RAID 0 device. At the
command prompt, enter these two commands:
mdadm --create /dev/md0 --run --level=0 --chunk=64 --raid-devices=2 /dev/
sdb1 /dev/sdc1
mdadm --create /dev/md1 --run --level=0 --chunk=64 --raid-devices=2 /dev/
sdd1 /dev/sde1
The default chunk size is 64 KB.
3 Create the nested RAID 0+1 device. At the command prompt, enter the following command
using the software RAID 0 devices you created in
mdadm --create /dev/md2 --run --level=1 --raid-devices=2 /dev/md0 /dev/md1
4 Create a file system on the RAID 0+1 device
For example, at the command prompt, enter
mkfs.reiserfs /dev/md2
Modify the command if you want to use a different file system.
5 Edit the
/etc/mdadm.conf
.
/dev/md2
6 Edit the
/etc/fstab
7 Reboot the server.
The RAID 0+1 device is mounted to

7.3 Creating a Complex RAID 10 with mdadm

Section 7.3.1, "Understanding the mdadm RAID10," on page 101
Section 7.3.2, "Creating a RAID10 with mdadm," on page 104

7.3.1 Understanding the mdadm RAID10

In , the RAID10 level creates a single complex software RAID that combines features of both
mdadm
RAID 0 (striping) and RAID 1 (mirroring). Multiple copies of all data blocks are arranged on
multiple drives following a striping discipline. Component devices should be the same size.
"Comparison of RAID10 Option and Nested RAID 10 (1+0)" on page 102
RAID 0 (stripe)
/dev/md0
/dev/md1
/dev/md2
file to add entries for the component devices and the RAID device
file to add an entry for the RAID 0+1 device
.
/local
RAID 0+1 (mirrored stripes)
/dev/md2
Step 2:
, such as a Reiser file system (reiserfs).
/dev/md2
Managing Software RAIDs 6 and 10 with mdadm 101
.