Creating Nested Raid 10 (0+1) With Mdadm - Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual

Table 10-3
Raw Devices
/dev/sdb1
/dev/sdc1
/dev/sdd1
/dev/sde1
1 Open a terminal console, then log in as the
2 Create 2 software RAID 1 devices, using two different devices for each RAID 1 device. At the
command prompt, enter these two commands:
mdadm --create /dev/md0 --run --level=1 --raid-devices=2 /dev/sdb1 /dev/
sdc1
mdadm --create /dev/md1 --run --level=1 --raid-devices=2 /dev/sdd1 /dev/
sde1
3 Create the nested RAID 1+0 device. At the command prompt, enter the following command
using the software RAID 1 devices you created in
mdadm --create /dev/md2 --run --level=0 --chunk=64 --raid-devices=2 /dev/
md0 /dev/md1
The default chunk size is 64 KB.
4 Create a file system on the RAID 1+0 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
/dev/md2
6 Edit the
7 Reboot the server.
The RAID 1+0 device is mounted to

10.2.3 Creating Nested RAID 10 (0+1) with mdadm

A nested RAID 0+1 is built by creating two to four RAID 0 (striping) devices, then mirroring them
as component devices in a RAID 1.
IMPORTANT: If you need to manage multiple connections to the devices, you must configure
multipath I/O before configuring the RAID devices. For information, see
Multipath I/O for Devices," on page
In this configuration, spare devices cannot be specified for the underlying RAID 0 devices because
RAID 0 cannot tolerate a device loss. If a device fails on one side of the mirror, you must create a
replacement RAID 0 device, than add it into the mirror.
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.
92 SLES 11: Storage Administration Guide
Scenario for Creating a RAID 10 (1+0) by Nesting
RAID 1 (mirror)
/dev/md0
/dev/md1
file to add entries for the component devices and the RAID device
/etc/mdadm.conf
.
file to add an entry for the RAID 1+0 device
/etc/fstab
user or equivalent.
root
Step 2:
, such as a Reiser file system (reiserfs).
/dev/md2
.
/local
43.
RAID 1+0 (striped mirrors)
/dev/md2
.
/dev/md2
Chapter 7, "Managing