Novell LINUX ENTERPRISE SERVER 10 SP2 - STORAGE ADMINISTRATION GUIDE 05-15-2009 Administration Manual page 56

"Configuring Default Multipath Behavior in /etc/multipath.conf" on page 58
"Applying Changes Made to the /etc/multipath.conf File" on page 58
Creating the multipath.conf File
If the
/etc/multipath.conf
1 In a terminal console, log in as the
2 Enter the following command (all on one line, of course) to copy the template:
cp /usr/share/doc/packages/multipath-tools/multipath.conf.synthetic /etc/
multipath.conf
3 Use the
as a reference to determine how to configure multipathing for your system.
4 Make sure there is an appropriate
documentation on the proper setup of the
The
/etc/multipath.conf
are using a storage subsystem that is automatically detected (see
Multipathing Support" on page
configuration of the
5 Save the file.
Verifying the Setup in the etc/multipath.conf File
After having set up the configuration, you can perform a "dry run" by entering
multipath -v3 -d
This command scans the devices, then displays what the setup would look like. The output is similar
to the following:
26353900f02796769
[size=127 GB]
[features="0"]
[hwhandler="1
\_ round-robin 0 [first]
\_ 1:0:1:2 sdav 66:240
\_ 0:0:1:2 sdr
\_ round-robin 0
\_ 1:0:0:2 sdag 66:0
\_ 0:0:0:2 sdc
Paths are grouped into priority groups. Only one priority group is ever in active use. To model an
active/active configuration, all paths end up in the same group. To model active/passive
configuration, the paths that should not be active in parallel are placed in several distinct priority
groups. This normally happens automatically on device discovery.
The output shows the order, the scheduling policy used to balance I/O within the group, and the
paths for each priority group. For each path, its physical address (host:bus:target:lun), device node
name, major:minor number, and state is shown.
56 SLES 10 SP2: Storage Administration Guide
file does not exist, copy the example to create the file:
/usr/share/doc/packages/multipath-tools/multipath.conf.annotated
file requires a different
48), the default entry for that device can be used; no further
/etc/multipath.conf
emc"]
[ready ]
65:16 [ready ]
[ready ]
8:32 [ready ]
user.
root
entry for your SAN. Most vendors provide
device
section.
device
device
file is required.
section for different SANs. If you
"Tested Storage Arrays for
file