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

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44 SLES 10 Storage Administration Guide for EVMS
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5.1.6 Multipath Tools
The
multipath-tools
user-space package takes care of automatic path discovery and grouping.
It 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.
The tools are described in the following table:
Table 5-2
Tools Available in the multipath-tools Package
For a list of files included in this package, see the multipath-tools Package Description (http://
www.novell.com/products/linuxpackages/suselinux/multipath-tools.html) .
Ensure that the multipath-tools package is installed by entering the following at a terminal console
prompt:
rpm -q multipath-tools
5.2 Before You Begin
Š Section 5.2.1, “Preparing SAN Devices for Multipathing,” on page 44
Š
Section 5.2.2, “Partitioning Devices that Have Multiple Paths,” on page 45
Š Section 5.2.3, “Configuring mdadm.conf and lvm.conf to Scan Devices by UUID,” on page 45
5.2.1 Preparing SAN Devices for Multipathing
Before configuring multipath I/O for your SAN devices, prepare the SAN devices, as necessary, by
doing the following:
Š
Configure and zone the SAN with the vendor’s tools.
Š
Configure permissions for host LUNs on the storage arrays with the vendor’s tools.
Š
Install the Linux HBA driver module. Upon module installation, the driver automatically scans
the HBA to discover any SAN devices that have permissions for the host. It presents them to
the host for further configuration.
NOTE: Ensure that the HBA driver you are using does not have native multipathing enabled.
Tool Description
multipath
Scans the system for multipathed devices and
assembles them.
multipathd
Waits for maps events then executes
multipath
.
devmap-name
Provides a meaningful device name to
udev
for
device maps (devmaps).
kpartx
Maps linear devmaps to partitions on the
multipathed device, which makes it possible to
create multipath monitoring for partitions on the
device.