Remove LUN from OCFS2

# ocfs2_hb_ctl -I -d /dev/mapper/backup2-backup2

508C2154503344E78ACD6CD6B000000: 2 refs

#The previous step will list the amount of refs (references to heartbeat)

# ocfs2_hb_ctl -K -d /dev/mapper/backup2-backup2 UUID ( repeat until refs = 0)

# lvdisplay /dev/backup2/backup2
--- Logical volume ---
LV Name /dev/backup2/backup2
VG Name backup2
LV UUID vvv1e5-W2Is-FyAT-MCTk-KcFv-mn2X-000000
LV Write Access read/write
LV Status available
# open 1
LV Size 2.93 TB
Current LE 768000
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:23

# vgdisplay backup2
--- Volume group ---
VG Name backup2
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 1
Act PV 1
VG Size 3.00 TB
PE Size 4.00 MB
Total PE 786431
Alloc PE / Size 768000 / 2.93 TB
Free PE / Size 18431 / 72.00 GB
VG UUID wRIeok-ZcMP-qJDV-0Qmz-KoDE-X8bv-000000

# vgchange -an backup2 (make sure that backup2 is listed as being deactivated)

# vgexport backup2 (make volume groups unknown to the system)

# vgdisplay backup2

# multipath -ll >/tmp/multipath.txt (check multipath disk status)
# more /tmp/multipath.txt

backup2 (360060e80104b493004f3239b00000000) dm-42 HITACHI,DF600F
[size=3.0T][features=0][hwhandler=0][rw]
\_ round-robin 0 [prio=1][active]
\_ 4:0:0:23 sday 67:32 [active][ready]
\_ round-robin 0 [prio=0][enabled]
\_ 3:0:0:23 sdw 65:96 [active][ready]

# multipath -f backup2 (flush a multipath device map specified as parameter, if unused)

# vim /etc/multipath.conf (comment out and remove the WWID and alias for backup2)
multipath {
wwid 360060e80104b493004f3239b00000000
alias backup2
}

# echo 1 > /sys/class/scsi_disk/4:0:0:23/device/delete (remove scsi_disks)
# echo 1 > /sys/class/scsi_disk/3:0:0:23/device/delete (remove scsi_disks)

# dmesg |grep error
device-mapper: table: 253:15: multipath: error getting device
device-mapper: ioctl: error adding target to table
device-mapper: table: 253:15: multipath: error getting device
device-mapper: ioctl: error adding target to table

# multipath -ll |grep fail (remove one path from AMS one time, and check the all multipath device stats if active)