Storix Software SBAdmin Device-Mapper Multipath Devices - Manual (Page 4)

underlying path device as the block special device used for mounting the filesystem. This causes problems
when the software attempts to query the device for size and geometry. The block special device listed in
the /etc/fstab file should be the dm-multipath device instead of an underlying path device. Verify that if your
/etc/fstab file is using the /dev/disk/by-uuid/* naming convention, that you change the entries to the dm-
multipath device name or the /dev/disk/by-name/* naming convention. This will prevent problems when
attempting to query the devices during system backups. Note, after changing fstab entries you may
need to recreate your initrd using the distributions mkinitrd command.
Migrating to DM-Multipath Devices
Creating boot media
With most devices on Linux, there is a single module that needs to be loaded for the device to become
visible to the operating system. In the case of dm-multipath devices, there could be two. One module for the
Host Bus Adapter or HBA and one for the device handler module. The device handler module is specific to
the type of SAN hardware you are using. If you know in advance that you are migrating to different
hardware, you can preselect the module for the HBA and the device handler to be loaded upon booting
from the boot media. For more information on pre-selecting modules, please refer to the “Customizing
Boot Media” section in the
SBAdmin Linux System Recovery Guide .
Discovering dm-multipath devices from the recovery media
If you are migrating from a non-multipath system, by default, the necessary modules required for the
operating system to discover the dm-multipath devices will not be available. Unless you have preselected
the modules to be loaded at boot-time, you will need to load additional drivers to make the dm-multipath
devices available to the operating system. In some cases, you may need to select both the module for the
HBA as well as the device handler for your SAN.
From the System Installation and Maintenance Main Menu, select System Recovery Utilities, select
Load Additional SCSI/FC Adapter Modules to display the following options:
Storix System Backup Administrator 4 Device-Mapper Multipath Guide
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