Chapter 2 Multipath Driver System Setup
2.1 Accessing the Storage System Disks
FUJITSU Storage ETERNUS Multipath Driver V2 User’s Guide for Linux
Copyright 2014 FUJITSU LIMITED
P2U3-0031-15ENZ0
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2.1.2.1
Setting the Recognition Order
Perform the following procedure to set the recognition order.
Procedure
1
Execute the "mpdconfig -s" command.
Set the storage system recognition order according to the on-screen instructions.
The "mpdconfig" command is installed in the /opt/FJSVmpd/bin directory. Only the root-level user may
execute the "mpdconfig" command.
[Example]
2
Restart the server.
If the recognition order set in
is different from the current order, the server must be restarted to
enable the setting. If the order is unchanged, the server does not need to be restarted.
•
Setting the storage system recognition order can prevent the relation between the device name and the
LU to be changed by a Fibre Channel switch specification. However, this cannot prevent the relation
between the device name and the LU to be changed by actual disk failure or LU expansion.
•
If this function is used to set the recognition order and a storage system then becomes unrecognizable for
some reason, the storage systems that should be recognized after the failed storage system will not be
recognized. For example, if the recognition order is set while three storage systems are connected, and
the second storage system fails, the third storage system will not be recognized either, even though it is
nominally normal status. This is to avoid the device names (/dev/sda, etc.) changing due to the storage
systems being recognized in a different order from the original setting.
•
When using Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, or SUSE Linux Enterprise Server 11
(Service Pack 1 or later), the recognition order setting function by Multipath Driver cannot be used. The
by-id names must be used.
•
If the LU that is allocated to LUN0 is changed, the storage system is not recognized. In this case, the rec-
ognition order setting must be cleared before changing the LU.
•
For a Storage Cluster configuration, the recognition order setting function cannot be used. The by-id
names must be used.
If only one LUN mapping is set up when a single storage system is connected to the server, it is not necessary
to use the recognition order setting function.
# /opt/FJSVmpd/bin/mpdconfig -s
