Multipath I/O Management Tools; Using Mdadm For Multipathed Devices - Novell LINUX ENTERPRISE SERVER 10 SP2 - STORAGE ADMINISTRATION GUIDE 05-15-2009 Administration Manual

If multiple paths are not automatically detected, you can configure them manually in the
file. The
multipath.conf
For information, see Section 5.4.5, "Creating and Configuring the /etc/multipath.conf File," on
page 55.

5.3.2 Multipath I/O Management Tools

The user-space package takes care of automatic path discovery and grouping. It
multipath-tools
automatically tests the path periodically, so that a previously failed path is automatically reinstated
when it becomes healthy again. This minimizes the need for administrator attention in a production
environment.
Tools in the multipath-tools Package
Table 5-2
Tool
multipath
multipathd
devmap-name
kpartx
For a list of files included in this package, see the
www.novell.com/products/linuxpackages/suselinux/multipath-tools.html).
1 Ensure that the
multipath-tools
console prompt:
rpm -q multipath-tools
If it is installed, the response repeats the package name and provides the version information,
such as:
multipath-tools-04.7-34.23
If it is not installed, the response reads:
package multipath-tools is not installed

5.3.3 Using mdadm for Multipathed Devices

In SUSE Linux Enterprise Server 10, Udev is the default device handler, and devices are
automatically known to the system by the Worldwide ID instead of by the device node name. This
resolves problems in previous releases where
recognize multipathed devices.
Just as for LVM2,
mdadm
node path. Therefore, the
DEVICE /dev/disk/by-id/*
This is the default handling in SUSE Linux Enterprise Server 10 and later, as noted above.
file does not exist until you create and configure it.
multipath.conf
Description
Scans the system for multipathed devices and assembles them.
Waits for maps events, then executes
Provides a meaningful device name to
Maps linear devmaps to partitions on the multipathed device, which makes
it possible to create multipath monitoring for partitions on the device.
multipath-tools Package Description (http://
package is installed by entering the following at a terminal
mdadm.conf
requires that the devices be accessed by the ID rather than by the device
entry in
DEVICE /etc/mdadm.conf
multipath .
udev for device maps (devmaps).
and did not properly
lvm.conf
should be set as follows:
Managing Multipath I/O for Devices
/etc/
51