Storix Software SBAdmin Device-Mapper Multipath Devices - Manual (Page 3)

Storix System Backup Administrator 3 Device-Mapper Multipath Guide
Copyright © 2014 Storix, Inc.
Storix is a registered trademark of Storix, Inc in the USA. SBAdmin is a trademark of Storix, Inc in the USA and other countries
SBAdmin will refer to all multipath devices with the path /dev/mpath/mpathX. If your backups do not
appear to include the data residing on your dm-multipath devices, verify that the devices are seen in the
/dev/mpath directory.
Having the devices in the /dev/mpath directory is required for device discovery. However, there are other
factors that can prevent device detection. There are four (4) different device naming schemes that SBAdmin
has been tested against that alternate the name of the disk and the prefix to the partition.
For the first partition on the first dm-multipath device it could be called one of the following:
/dev/mpath/mpath[0-9]p[1-15] /dev/mpath/mpath[a-z]p[1-15]
/dev/mpath/mpath[0-9]-part[1-15] /dev/mpath/mpath[a-z]-part[1-15]
If you are using an alias line in your /etc/multipath.conf file, you could also find that the alias is used
instead of the word mpath. For example: /dev/mpath/mydisk0-part1. There are limitless numbers of
combinations you could have for naming your devices. SBAdmin has a configuration file that is used as a
reference file for device naming schemes. This file is /opt/storix/config/device_info. Currently we have
entries for the two of the most common naming conventions uncommented in this list. In most cases you
will not need to update this file. However, you may need to edit this file to match the naming scheme in your
environment. Make sure to comment out any naming scheme that you are not using to prevent
confusion.
##############
# Multipath (device-mapper)
##############
# The following defines up 16 devices, 15 partitions per device
# Because different linux distributions use varying udev rules
# uncomment the device names that match your environment
disk:mpath/mpath:0-15:p:1-15:Device-Mapper Multipath device
disk:mpath/mpath:a-p:-part:1-15:Device-Mapper Multipath device
#disk:mpath/mpath:a-p:p:1-15:Device-Mapper Multipath device
#disk:mpath/mpath:0-15:-part:1-15:Device-Mapper Multipath device
If you are using an alias, you will need to create an entry for your own naming scheme. As in the example
above for /dev/mpath/mydisk0-part1, the entry would be:
disk:mpath/mydisk:0-15:-part:1-15:Device-Mapper Multipath device
So that changes to this file are not lost after software updates, copy the edited file to your storix config
folder inside your storix data directory. By default this would be /storix/config on the client that is using
dm-multipath devices.
# cp /opt/storix/config/device_info /storix/config/device_info
Entries in /etc/fstab
Different Linux distributions handle dm-multipath devices in different ways. One of the areas that can cause
problems with the SBAdmin software is the mount entries in the /etc/fstab file. Some distributions use an