HP 3PAR Ubuntu Operating System Implementation Guide

4 Modifying HP 3PAR Devices on the Host Server
Creating Device-mapper Devices
Complete the following steps to create Device-mapper devices.
1. Run the multipath command to create new Device-mapper nodes under the /dev/mapper
directory.
# multipath
2. Verify the Device-mapper devices have been created by issuing multipath -11.
For example, in the following Ubuntu host output, the /dev/mapper/350002ac0000b011b
Device-mapper node is seen from device sdc on driver instance (2:0:2:99) and from sde on
driver instance (3:0:0:99).
* multipath -ll
350002ac0000b011b dm-5 3PARdata,VV
size=5.0G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 7:0:0:12 sdaf 65:240 active ready running
|- 6:0:0:12 sdai 66:32 active ready running
|- 8:0:0:12 sdao 66:128 active ready running
`- 5:0:0:12 sdal 66:80 active ready running
3. After creating the devices, use the multipath -v 3 command to retrieve more detailed
information about Device-mapper nodes and their associated paths.
4. In the following example output from a Ubuntu 12.10 host, the /dev/mapper/
350002ac001dc0031 Device-mapper node is from device sdc seen on driver instance
(2:0:2:99) and sde seen on driver instance (3:0:0:99). Verify the following:
• The path checker is set to tur for each of the devices.
• The variable no_path_retry is set to a value of 18 for iSCSI.
Example for Ubuntu 12.04.2:
# multipath -v 3
May 17 13:18:32 | sda: not found in pathvec
May 17 13:18:32 | sda: mask = 0x1f
May 17 13:18:32 | sda: dev_t = 8:0
May 17 13:18:32 | sda: size = 104857600
May 17 13:18:32 | sda: subsystem = scsi
May 17 13:18:32 | sda: vendor = 3PARdata
May 17 13:18:32 | sda: product = VV
May 17 13:18:32 | sda: rev = 3122
May 17 13:18:32 | sda: h:b:t:l = 7:0:0:0
May 17 13:18:32 | sda: tgt_node_name = 0x2ff70002ac0185e
May 17 13:18:32 | sda: serial = 1699811
May 17 13:18:32 | sda: get_state
May 17 13:18:32 | loading /lib/multipath/libchecktur.so checker
May 17 13:18:32 | sda: path checker = tur(controller setting)
May 17 13:18:32 | sda: state = running
May 17 13:18:32 | sda: state = 3
May 17 13:18:32 | sda: prio = const(controller setting)
May 17 13:18:32 | sda: prio args = (null) (controller setting)
May 17 13:18:32 | sda: const prio = 1
May 17 13:18:32 | sda: getuid = /lib/udev/scsi_id--whitelisted --device=/dev/%n
(controller setting
28 Modifying HP 3PAR Devices on the Host Server