Installation guide

/sbin/start_udev
Networked storage devices with configured rules now have persistent names on all hosts where the
files were updated This means you can migrate guests between hosts using the shared storage and
the guests can access the storage devices in their configuration files.
Mu lt ip le pat h co n f ig u rat io n
The multipath package is used for systems with more than one physical path from the computer to
storage devices. multipath provides fault tolerance, fail-over and enhanced performance for
network storage devices attached to Red Hat Enterprise Linux systems.
Implementing LUN persistence in a multipath environment requires defined alias names for your
multipath devices. Each storage device has a UUID which acts as a key for the aliased names.
Identify a device's UUID using the scsi_id command.
# scsi_id -g -s /block/sdc
The multipath devices will be created in the /dev/mpath directory. In the example below 4 devices
are defined in /etc/multipath.conf:
multipaths {
multipath {
wwid 3600805f30015987000000000768a0019
alias oramp1
}
multipath {
wwid 3600805f30015987000000000d643001a
alias oramp2
}
mulitpath {
wwid 3600805f3001598700000000086fc001b
alias oramp3
}
mulitpath {
wwid 3600805f300159870000000000984001c
alias oramp4
}
}
This configuration will create 4 LUNs named /dev/mpath/oramp1, /dev/mpath/oramp2,
/dev/mpath/oramp3 and /dev/mpath/oramp4. Once entered, the mapping of the devices' WWID
to their new names are now persistent after rebooting.
9.4. Add a virt ualized CD-ROM or DVD device t o a guest
To attach an ISO file to a guest while the guest is online use virsh with the attach-disk
parameter.
# virsh attach-disk [domain-id] [source] [target] --driver file --type cdrom --mode
readonly
The source and target parameters are paths for the files and devices, on the host and guest
respectively. The source parameter can be a path to an ISO file or the device from the /dev directory.
⁠Chapt er 9 . Virt ualized st orage devices
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