Dell PowerVault MD Series, Administrator'S Manual

Page: 177 / 237

Display The Multipath Device Topology Using The Multipath Command
The multipath command adds newly scanned and mapped virtual disks to the Device Mapper tables and creates entries
for them in the/dev/mapper directory on the host server. These devices are the same as any other block devices in the
host.
To list all the multipath devices, run the following command:
# multipath –ll
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 controller for the device.
Sdb
is the physical path to the non-owning controller 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 controller for the device.
Sdcl
is the physical path to the non-owning controller for the device.
Create A New fdisk Partition On A 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 on fdisk.
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