Installation guide

devices
Settings for the individual storage controllers. T hese values overwrite what is specified in the
defaults section of the configuration file. If you are using a storage array that is not
supported by default, you may need to create a devices subsection for your array.
When the system determines the attributes of a multipath device, first it checks the multipath settings,
then the per devices settings, then the multipath system defaults.
4.2. Configuration File Blacklist
The devnode_blacklist section of the multipath configuration file specifies the devices that will not
be used when the system configures multipath devices. Devices that are blacklisted will not be grouped
into a multipath device.
By default, all devices are blacklisted, since the following lines appear in the initial configuration file.
devnode_blacklist {
devnode "*"
}
To enable multipathing on all of the devices that are supported by default, comment out those lines, as
described in Section 3.1, “Setting Up DM-Multipath”.
After commenting out the universal blacklist, you can specify general device types and individual devices
to blacklist. You can blacklist devices according to the following criteria:
By WWID, as described in Section 4.2.1, “Blacklisting By WWID”
By device name, as described in Section 4.2.2, “Blacklisting By Device Name”
By default, a variety of device types are blacklisted, even after you comment out the initial
devnode_blacklist section of the configuration file. For information, see Section 4.2.2, “Blacklisting
By Device Name”.
4.2.1. Blacklisting By WWID
You can specify individual devices to blacklist by their World-Wide IDentification with a wwid entry in the
blacklist section of the configuration file.
The following example shows the lines in the configuration file that would blacklist a device with a WWID
of 26353900f02796769.
blacklist {
wwid 26353900f02796769
}
4.2.2. Blacklisting By Device Name
You can blacklist device types by device name so that they will not be grouped into a multipath device by
specifying a devnode entry in the devnode_blacklist section of the configuration file.
The following example shows the lines in the configuration file that would blacklist all SCSI devices, since
it blacklists all sd* devices.
Chapter 4. The DM-Multipath Configuration File
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