The Virtualization Cookbook for SLES 10 SP2 - z/VM - IBM

# ls
access_denied in_recovery status unit_add
failed power uevent unit_remove
# echo 0x4020400800000000 > unit_add
# cat /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 00 Lun: 1074282528
Vendor: IBM Model: 2107900 Rev: .310
Type: Direct-Access ANSI SCSI revision: 05
Host: scsi1 Channel: 00 Id: 00 Lun: 1074282528
Vendor: IBM Model: 2107900 Rev: .310
Type: Direct-Access ANSI SCSI revision: 05
► At this point the system thinks there are two LUNs, but actually there are two paths to the
same LUN.
► Install the device-mapper-multipath RPM:
# yum -y install device-mapper-multipath
...
► Create a file /etc/multipath.conf:
# cd /etc
# vi multipath.conf
defaults {
user_friendly_names yes
}
► Turn the multipath service on for this session and across reboots:
# service multipathd start
Starting multipathd daemon: [ OK ]
# chkconfig multipathd on
# multipath -ll
mpatha (36005076305ffc73d0000000000002008) dm-4 IBM,2107900
size=8.0G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
|- 0:0:0:1074282528 sda 8:0 active ready running
`- 1:0:0:1074282528 sdb 8:16 active ready running
► Add an entry to /etc/multipath.conf using the mpatha value (WWID)
defaults {
user_friendly_names yes
}
# create a friendly name - test_lun
multipaths {
multipath {
wwid 36005076305ffc73d0000000000002008
alias test_lun
no_path_retry 5
}
}
► Restart the multipath service and verify that the new test_lun friendly name has been
added:
]# service multipathd restart
Stopping multipathd daemon: [ OK ]
Starting multipathd daemon: [ OK ]
[root@train4 etc]# ls /dev/mapper
control system_vg-tmp_lv system_vg-var_lv test_lunp1
system_vg-opt_lv system_vg-usr_lv test_lun
204 The Virtualization Cookbook for RHEL 6