HP 3PAR SUSE Linux Enterprise Implementation Guide

Check for the installed multipath tools package.
# rpm -qa |grep multipath
multipath-tools-0.4.7-34.38
The following commands are user-space processes:
• multipath inspects Linux devices to see if there are multiple paths to the same device and
communicates to the kernel Device-mapper to set up a device map (dm) device for the device
and is responsible for the path coalescing and device map creation.
• The multipathd daemon checks path health and will reconfigure the multipath map whenever
a path comes up or goes down so as to maintain correctly the path mapping state.
• kpartx reads partition tables on specified devices and creates device maps over partition
segments that are detected.
Device-mapper also depends on the udev and sysfsutils filesystem packages. udev is a user
space process which dynamically manages the creation of devices under the /dev/ file system.
The sysfsutils package exports the view of the system hardware configuration to udev user
space process for device node creation. These packages must be present on the system.
For example:
# rpm -qa | grep udev
udev-128-13.1
# rpm -qa | grep sysfs
sysfsutils-2.1.0-102.18
If an /etc/multipath.conf file does not exist, create one using the
/usr/share/doc/packages/multipath-tools/ multipath.conf.synthetic file as
a template. You can find definition of the version parameters found for multipath.conf in the
/usr/share/doc/packages/multipath-tools/multipath.conf.annotated file.
Modifying the /etc/multipath.conf File
The /etc/multipath.conf file is used by Device-mapper where the multipathing parameters
have been set. The default installed /etc/multipath.conf file must be edited with the following
changes for a minimum configuration connecting to an HP 3PAR StoreServ Storage array. Entries
listed in multipath.conf override the default kernel parameters for dm-multipath. In general,
the kernel defaults are sufficient with the exception of the devices entries for HP 3PAR. In the specific
case of booting the host from an HP 3PAR StoreServ Storage volume (a.k.a. SAN boot), there are
additional default considerations:
NOTE: See “Booting the Host from the HP 3PAR StoreServ Storage” (page 64) for SAN boot
requirements.
See also the SUSE Enterprise Linux Server Storage Administration Guide and online docs in the
/usr/share/doc/packages/multipath-tools folder.
1. Remove or comment out all entries in the /etc/multipath.conf file except for the devices
files of devices currently in use.
Setting Up Multipathing Software 31