Administrator Guide

The output must be similar to this example, which shows the output for one mapped virtual disk.
mpath1 (3600a0b80005ab177000017544a8d6b92) dm-0 DELL, MD3xxxx[size=5.0G][features=3
queue_if_no_path pg_init_retries 50][hwhandler=1 rdac][rw]\_ round-robin 0 [prio=6][active]
\_ 5:0:0:0 sdc 8:32 [active][ready]\_ round-robin 0 [prio=1][enabled] \_ 4:0:0:0 sdb
8:16 [active][ghost]
where:
mpath1 is the name of the virtual device created by device mapper. It is located in the /dev/mapper directory.
DELL is the vendor of the device.
MD3xxxx is the model of the device.
Sdc is the physical path to the owning RAID for the device.
Sdb is the physical path to the nonowning RAID for the device.
The following is an example of SLES output:
mpathb(360080e500017b2f80000c6ca4a1d4ab8) dm-21 DELL,MD3xxxx[size=1.0G][features=3
queue_if_no_path pg_init_retries 50][hwhandler=1 rdac][rw]\_ round-robin 0 [prio=6][active]
\_ 4:0:0:22 sdx 65:112 [active][ready]\_ round-robin 0 [prio=1][enabled] \_ 6:0:0:22 sdcl
69:144 [active][ghost]
where:
mpathb is the name of the virtual device created by device mapper. It is located in the /dev/mapper directory.
DELL is the vendor of the device.
MD3xxxx is the model of the device.
Sdx is the physical path to the owning RAID for the device.
Sdcl is the physical path to the nonowning RAID for the device.
Create fdisk partition on multipath device node
The fdisk command allows creation of partition space for a file system on the newly scanned and mapped virtual disks that have been
presented to Device Mapper.
To create a partition with the multipathing device nodes /dev/mapper/mpath<x>, for example, use the following command:
# fdisk /dev/mapper/mpath<x>
where mpath<x> is the multipathing device node on which you want to create the partition.
NOTE:
The <x> value is an alphanumeric operating system-dependent format. The corresponding value for mapped
virtual disks can be seen using the previously run multipath command. See your operating system documentation for
additional information about fdisk.
Add new partition to Device Mapper
The kpartx command adds the new fdisk partition to the Device Mapper list of usable partitions. See examples below, where mpath<x>
is the device node on which the partition was created.
# kpartx –a /dev/mapper/mpath<x>
If successful, the command does not display an output. To verify success and view exact partition naming, you can use these commands
to see the full partition names assigned.
# cd /dev/mapper# ls
The following are some examples of the general mapping formats:
• On Red Hat Enterprise Linux (RHEL) hosts, a partition node has the format:/dev/mapper/mpath<y>p<y>
Device Mapper multipath for Linux
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