HP 3PAR SUSE Linux Enterprise Implementation Guide

7 Modifying HP 3PAR Devices on the Host
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 SUSE host output, the /dev/mapper/350002ac001dc0031
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
350002ac001dc0031 dm-0 3PARdata,VV
[size=2.0G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=2][active]
\_ 2:0:2:99 sdc 8:32 [active][ready]
\_ 3:0:0:99 sde 8:64 [active][ready]
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 SUSE 11 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 no_path_retry is set to a value of 12 for iSCSI and 18 for Fibre Channel.
Example for SUSE 11:
# multipath -v 3
Oct 19 09:33:46 | sdc: not found in pathvec
Oct 19 09:33:46 | sdc: mask = 0x1f
Oct 19 09:33:46 | sdc: dev_t = 8:32
Oct 19 09:33:46 | sdc: size = 4194304
Oct 19 09:33:46 | sdc: subsystem = scsi
Oct 19 09:33:46 | sdc: vendor = 3PARdata
Oct 19 09:33:46 | sdc: product = VV
Oct 19 09:33:46 | sdc: rev = 0000
Oct 19 09:33:46 | sdc: h:b:t:l = 2:0:2:99
Oct 19 09:33:46 | sdc: tgt_node_name = 0x2ff70002ac00003
Oct 19 09:33:46 | sdc: serial = 01DC0031
Oct 19 09:33:46 | sdc: get_state
Oct 19 09:33:46 | loading /lib/multipath/libchecktur.so checker
Oct 19 09:33:46 | sdc: path checker = tur (controller setting)
Oct 19 09:33:46 | sdc: state = up
Oct 19 09:33:46 | sdc: getuid = /lib/udev/scsi_id -g -u -d /dev/%n (controller setting)
Oct 19 09:33:46 | sdc: uid = 350002ac001dc0031 (callout)
Oct 19 09:33:46 | sdc: prio = const (controller setting)
Oct 19 09:33:46 | sdc: const prio = 1
Oct 19 09:33:46 | sde: not found in pathvec
Oct 19 09:33:46 | sde: mask = 0x1f
Oct 19 09:33:46 | sde: dev_t = 8:64
Oct 19 09:33:46 | sde: size = 4194304
Oct 19 09:33:46 | sde: subsystem = scsi
Oct 19 09:33:46 | sde: vendor = 3PARdata
Oct 19 09:33:46 | sde: product = VV
Oct 19 09:33:46 | sde: rev = 0000
Oct 19 09:33:46 | sde: h:b:t:l = 3:0:0:99
Oct 19 09:33:46 | sde: tgt_node_name = 0x2ff70002ac00003
Oct 19 09:33:46 | sde: serial = 01DC0031
Oct 19 09:33:46 | sde: get_state
Oct 19 09:33:46 | sde: path checker = tur (controller setting)
Oct 19 09:33:46 | sde: state = up
Oct 19 09:33:46 | sde: getuid = /lib/udev/scsi_id -g -u -d /dev/%n (controller setting)
Oct 19 09:33:46 | sde: uid = 350002ac001dc0031 (callout)
Oct 19 09:33:46 | sde: prio = const (controller setting)
Oct 19 09:33:46 | sde: const prio = 1
Creating Device-mapper Devices 57