Creating A Complex Raid 10 With Mdadm; Understanding The Mdadm Raid10 - Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual

Scenario for Creating a RAID 10 (0+1) by Nesting
Table 10-4
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 two 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

10.3 Creating a Complex RAID 10 with mdadm

Section 10.3.1, "Understanding the mdadm RAID10," on page 93
Section 10.3.2, "Creating a RAID 10 with mdadm," on page 96

10.3.1 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.
"Comparing the Complex RAID10 and Nested RAID 10 (1+0)" on page 94
"Number of Replicas in the mdadm RAID10" on page 94
"Number of Devices in the mdadm RAID10" on page 94
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
.
93