HP 3PAR SUSE Linux Enterprise Implementation Guide

Use fdisk on the underlying disks /dev/sdXX and execute the following command when
Device-mapper multipath maps the device to create a /dev/mapper/<device node> partition.
# multipath -l
50002ac001b40031
[size=5 GB][features="1 queue_if_no_path"][hwhandler="0"]
\_ round-robin 0 [active]
\_ 0:0:0:0 sda 8:0 [active]
\_ 1:0:0:0 sdb 8:16 [active]
Device-mapper node 350002ac001b40031 is formed from underlying devices sda and sdb
representing two paths from the same storage volume.
# fdisk /dev/sda -- create a partition
After the fdisk command completes, use the kpartx command to list and create DM devices
for the partitions on the device.
# kpartx /dev/mapper/350002ac001b40031
350002ac001b40031p1 : 0 10477194 /dev/mapper/350002ac001b40031 62
# kpartx -a /dev/mapper/350002ac001b40031 -- will add a partition mapping
# ls /dev/mapper
350002ac001b40031 350002ac001b40031p1
where 350002ac001b40031p1 is a partition device of whole disk 350002ac001b40031.
WARNING! While using fdisk, make sure the correct underlying device is used. Use the
multipath command to identify the underlying device.
WARNING! All I/O creating the file system and mount points needs to be done using the
Device-mapper device nodes /dev/mapper/XXX.
Data corruption will occur if any I/O is attempted on /dev/sdX device nodes.
WARNING! Issuing the multipath -F command will flush out all the Device-mapper mapping
and can be very destructive if I/O is being served to any of the existing devices. Avoid using the
-F option.
Use kpartx to delete a Device-mapper instance and then use fdisk to delete the partition.
The Device-mapper node name represents the storage volume ID (excluding the first digit 3). Use
the HP 3PAR OS CLI showvv or showvlun commands to get the volume name it represents.
Example:
1. On your FC connected host run ls /dev/mapper.
# ls /dev/mapper
350002ac001b40031
2. Run the showvlun command on the HP 3PAR StoreServ Storage using the output above
(minus first digit).
# showvlun -lvw -a |grep -i 50002ac001b40031
0 testvlun 50002AC001B40031 susehost 2100001B321A0C63 0:4:1 host
0 testvlun 50002AC001B40031 susehost 2101001B323A0C63 1:5:1 host
60 Modifying HP 3PAR Devices on the Host