Novell LINUX ENTERPRISE SERVER 10 - STORAGE ADMINISTRATION GUIDE FOR EVMS, Administration Manual

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Managing Software RAIDs with EVMS 59
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6.1.8 Multi-Disk Plug-In for EVMS
The Multi-Disk (
md
) plug-in supports creating software RAIDs 0 (striping), 1 (mirror), 4 (striping
with dedicated parity), and 5 (striping with distributed parity). The MD plug-in to EVMS allows you
to manage all of these MD features as “regions” with the Regions Manager.
6.1.9 Device Mapper Plug-In for EVMS
The Device Mapper plug-in supports the following features in the EVMS MD Region Manager:
Š Multipath I/O: Connection fault tolerance and load balancing for connections between the
server and disks where multiple paths are available. If you plan to use multipathing, you should
configure MPIO for the devices that you plan to use in the RAID before configuring the RAID
itself. For information, see
Chapter 5, “Managing Multipath I/O for Devices,” on page 41 .
IMPORTANT: The EVMS interface manages multipathing under the MD Region Manager,
which originally supported the
md multipath
functions. It uses the legacy
md
terminology
in the interface and in naming of device nodes, but implements the storage objects with Device
Mapper.
Š
Linear RAID: A linear concatenation of discontinuous areas of free space from the same or
multiple storage devices. Areas can be of different sizes.
Š
Snapshots: Snapshots of a file system at a particular point in time, even while the system is
active, thereby allowing a consistent backup
The Device Mapper driver is not started by default in the rescue system.
1 Open a terminal console, then log in as the
root
user or equivalent.
2 Start the Device Mapper by entering the following at the terminal console prompt:
/etc/init.d/boot.device-mapper start
6.2 Creating and Configuring a Software RAID
1 Open a terminal console, then log in as the
root
user or equivalent.
2 Start the EVMS GUI by entering the following at the terminal console prompt:
evmsgui
3 If the disks have not been initialized, initialize them by adding the DOS Segment Manager
now.
The following instructions assume you are initializing new disks. For information about
initializing an existing disk or a disk moved from another system, see
Section 4.2, “Initializing
Disks,” on page 34 .
Repeat the following steps for each disk that you want to initialize:
3a Select Actions > Add > Segment Manager to Storage Object .
3b From the list, select the DOS Segment Manager , then click Next .
3c Select the device, then click Add to initialize it.
4 If segments have not been created on the disks, create a segment on each disk that you plan to
use in the RAID.
For x86 platforms, this step is optional if you treat the entire disk as one segment.