Scan / Detect New Luns In Redhat Linux & Outputs To Remember

You use the below commands to identify existing LUNS and How to add newly mapped LUNS to Linux.

Check the current attached disks

#cat /proc/scsi/scsi | egrep -i 'Host:' | wc -l

#fdisk -l 2>/dev/null | egrep '^Disk' | egrep -v 'dm-' | wc -l

Check current multipath setup using multipath or powermt command

# multipath -l
mpath2 (36006016015501c0018c07c18e0d8dc11)
[size=68 GB][features="1 queue_if_no_path"][hwhandler="1 emc"]
\_ round-robin 0 [active]
\_ 0:0:0:2 sdc 8:32  [active]
\_ round-robin 0 [enabled]
\_ 1:0:0:2 sdi 8:128 [active]

mpath1 (36006016015501c0084227c0ee0d8dc11)
[size=68 GB][features="1 queue_if_no_path"][hwhandler="1 emc"]
\_ round-robin 0 [active]
\_ 1:0:0:1 sdh 8:112 [active]
\_ round-robin 0 [enabled]
\_ 0:0:0:1 sdb 8:16  [active]

mpath0 (36006016015501c00b6de3705e0d8dc11)
[size=68 GB][features="1 queue_if_no_path"][hwhandler="1 emc"]
\_ round-robin 0 [active]
\_ 0:0:0:0 sda 8:0   [active]
\_ round-robin 0 [enabled]
\_ 1:0:0:0 sdg 8:96  [active]

mpath7 (36006016015501c00c640c362d2c4df11)
[size=68 GB][features="1 queue_if_no_path"][hwhandler="1 emc"]
\_ round-robin 0 [active]
\_ 1:0:0:7 sdp 8:240 [active]
\_ round-robin 0 [enabled]
\_ 0:0:0:7 sdo 8:224 [active]

mpath6 (36006016015501c0016a5cfc0827add11)
[size=70 GB][features="1 queue_if_no_path"][hwhandler="1 emc"]
\_ round-robin 0 [active]
\_ 0:0:0:6 sdm 8:192 [active]
\_ round-robin 0 [enabled]
\_ 1:0:0:6 sdn 8:208 [active]

mpath5 (36006016015501c009826282ce0d8dc11)
[size=68 GB][features="1 queue_if_no_path"][hwhandler="1 emc"]
\_ round-robin 0 [active]
\_ 1:0:0:5 sdl 8:176 [active]
\_ round-robin 0 [enabled]
\_ 0:0:0:5 sdf 8:80  [active]

mpath4 (36006016015501c0096e1a824e0d8dc11)
[size=68 GB][features="1 queue_if_no_path"][hwhandler="1 emc"]
\_ round-robin 0 [active]
\_ 0:0:0:4 sde 8:64  [active]
\_ round-robin 0 [enabled]
\_ 1:0:0:4 sdk 8:160 [active]

mpath3 (36006016015501c0019c07c18e0d8dc11)
[size=68 GB][features="1 queue_if_no_path"][hwhandler="1 emc"]
\_ round-robin 0 [active]
\_ 1:0:0:3 sdj 8:144 [active]
\_ round-robin 0 [enabled]
\_ 0:0:0:3 sdd 8:48  [active]

#

If EMC powerpath installed check disk /multipath status as below

# powermt display dev=all | more
Pseudo name=emcpowerb
CLARiiON ID=APM00080503154 [cl10083]
Logical device ID=6006016023041F003AB6ED708885DD11 [LUN 3]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP A, current=SP A       Array failover mode: 1
==============================================================================
---------------- Host ---------------   - Stor -   -- I/O Path -  -- Stats ---
###  HW Path                I/O Paths    Interf.   Mode    State  Q-IOs Errors
==============================================================================
3 qla2xxx                   sde       SP A2     active  alive      0      1
3 qla2xxx                   sdh       SP B3     active  alive      0      0
6 qla2xxx                   sdk       SP A3     active  alive      0      1
6 qla2xxx                   sdn       SP B2     active  alive      0      0

Pseudo name=emcpowerc
CLARiiON ID=APM00080503154 [cl10083]
Logical device ID=6006016023041F007AE5EB628885DD11 [LUN 1]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP A, current=SP A       Array failover mode: 1
==============================================================================
---------------- Host ---------------   - Stor -   -- I/O Path -  -- Stats ---
###  HW Path                I/O Paths    Interf.   Mode    State  Q-IOs Errors
==============================================================================
3 qla2xxx                   sdc       SP A2     active  alive      0      1
3 qla2xxx                   sdf       SP B3     active  alive      0      0
6 qla2xxx                   sdi       SP A3     active  alive      0      1
6 qla2xxx                   sdl       SP B2     active  alive      0      0

Pseudo name=emcpowera
CLARiiON ID=APM00080503154 [cl10083]
Logical device ID=6006016023041F00AAE0FF698885DD11 [LUN 2]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0
Owner: default=SP B, current=SP B       Array failover mode: 1
==============================================================================
---------------- Host ---------------   - Stor -   -- I/O Path -  -- Stats ---
###  HW Path                I/O Paths    Interf.   Mode    State  Q-IOs Errors
==============================================================================
3 qla2xxx                   sdd       SP A2     active  alive      0      1
3 qla2xxx                   sdg       SP B3     active  alive      0      0
6 qla2xxx                   sdj       SP A3     active  alive      0      1
6 qla2xxx                   sdm       SP B2     active  alive      0      0

Scan for LUNS

Note this is for 2.6 kernel

# ls /sys/class/fc_host
host0  host1

#echo "1" > /sys/class/fc_host/host0/issue_lip
#echo "- - -" > /sys/class/scsi_host/host0/scan
#echo "1" > /sys/class/fc_host/host1/issue_lip
#echo "- - -" > /sys/class/scsi_host/host1/scan

Multpath Daemon and Powerpath (EMC)

Multipath will automatically add new native devices to multipathed

For powermt we need to configure like below

#powermt config

Other options to scan

If we know the channel , target ID , Lun address we can scan using that. Here we have 4 HBA emulex cards 0 1 2 3

server1:/proc/scsi/lpfc# ls
0  1  2  3

Through card 0 and 2

server1:/proc/scsi/lpfc# cat 0
lpfc0t00 DID d200ef WWPN 50:06:01:68:39:a0:43:65 WWNN 50:06:01:60:b9:a0:43:65
lpfc0t01 DID d201ef WWPN 50:06:01:61:39:a0:43:65 WWNN 50:06:01:60:b9:a0:43:65
server1:#/proc/scsi/lpfc# cat 1
server1:/proc/scsi/lpfc# cat 2
lpfc2t01 DID ed0cef WWPN 50:06:01:69:39:a0:43:65 WWNN 50:06:01:60:b9:a0:43:65
lpfc2t00 DID ed0def WWPN 50:06:01:60:39:a0:43:65 WWNN 50:06:01:60:b9:a0:43:65
server1:/proc/scsi/lpfc# cat 3
server1:/proc/scsi/lpfc#

It have same WWNN(World Wide Node Name) for all the 4 WWPN (World Wide Port Name)

server1:/proc/scsi/lpfc# cat /sys/class/fc_transport/*/node_name
0x50060160b9a04365
0x50060160b9a04365
0x50060160b9a04365
0x50060160b9a04365

server1:/proc/scsi/lpfc# grep 50060160b9a04365 /sys/class/fc_transport/*/node_name
/sys/class/fc_transport/target0:0:0/node_name:0x50060160b9a04365
/sys/class/fc_transport/target0:0:1/node_name:0x50060160b9a04365
/sys/class/fc_transport/target2:0:0/node_name:0x50060160b9a04365
/sys/class/fc_transport/target2:0:1/node_name:0x50060160b9a04365
server1:/proc/scsi/lpfc#

This indicates there are four Fibre Channel routes to this target.

Line 1 : Thru host 0 channel 0 target 0
Line 2 : Thru host 0 channel 0 target 1
Line 3 : Thru host 2 channel 0 target 0
Line 4 : thru host 2 channel 0 targer 1

So now can scan for LUNS as follows and Addresss "8" is given by storage Team

echo "0 0 8" > /sys/class/scsi_host/host0/scan
echo "0 1 8" > /sys/class/scsi_host/host0/scan
echo "0 0 8" > /sys/class/scsi_host/host2/scan
echo "0 1 8" > /sys/class/scsi_host/host2/scan

Output of SCSI file for reference

Host: scsi0 Channel: 00 Id: 00 Lun: 08
Vendor: DGC      Model: RAID 5           Rev: 0326
Type:   Direct-Access                    ANSI SCSI revision: 04
Host: scsi0 Channel: 00 Id: 01 Lun: 08
Vendor: DGC      Model: RAID 5           Rev: 0326
Type:   Direct-Access                    ANSI SCSI revision: 04
Host: scsi2 Channel: 00 Id: 00 Lun: 08
Vendor: DGC      Model: RAID 5           Rev: 0326
Type:   Direct-Access                    ANSI SCSI revision: 04
Host: scsi2 Channel: 00 Id: 01 Lun: 08
Vendor: DGC      Model: RAID 5           Rev: 0326
Type:   Direct-Access                    ANSI SCSI revision: 04