==== Linux on PPC ====

List devices slots, virtual and physical with position into the server:
<cli prompt='#'>
samba:~ # lsslot 
Getting node types 0x00000007

DR nodes list
==============
/proc/device-tree/vdevice: 
        drc index: 0x30000009        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C9
        loc code: 
/proc/device-tree/vdevice: 
        drc index: 0x30000008        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C8
        loc code: 
/proc/device-tree/vdevice: 
        drc index: 0x30000007        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C7
        loc code: 
/proc/device-tree/vdevice: 
        drc index: 0x30000006        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C6
        loc code: 
/proc/device-tree/vdevice: 
        drc index: 0x30000005        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C5
        loc code: 
/proc/device-tree/vdevice: 
        drc index: 0x30000004        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C4
        loc code: 
/proc/device-tree/vdevice/v-scsi@30000003: 
        drc index: 0x30000003        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C3
        loc code: 
/proc/device-tree/vdevice/l-lan@30000002: 
        drc index: 0x30000002        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C2
        loc code: 
/proc/device-tree/vdevice: 
        drc index: 0x30000001        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C1
        loc code: 
/proc/device-tree/vdevice/vty@30000000: 
        drc index: 0x30000000        description: Virtual I/O Slot
        drc name: U7895.22X.069581B-V7-C0
        loc code: 

# Slot                   Description       Linux Name    Device(s)
U7895.22X.069581B-V7-C0  Virtual I/O Slot  30000000      vty
U7895.22X.069581B-V7-C2  Virtual I/O Slot  30000002      l-lan
U7895.22X.069581B-V7-C3  Virtual I/O Slot  30000003      v-scsi
</cli>

List SCSI devices:
<cli prompt='#'>
samba:~ # lsscsi 
[0:0:1:0]    disk    AIX      VDASD            0001  /dev/sda 
[0:0:2:0]    disk    AIX      VDASD            0001  /dev/sdb 
[0:0:3:0]    disk    AIX      VDASD            0001  /dev/sdc 
[0:0:4:0]    disk    AIX      VDASD            0001  /dev/sdd 
[0:0:5:0]    disk    AIX      VDASD            0001  /dev/sde 
</cli>

List multipath devices:
<cli prompt='#'>
samba:~ # multipath -ll
360080e500018110000000a95524cd2a5 dm-11 AIX     ,VDASD           
size=250G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
  `- 0:0:3:0 sdc 8:32 active ready running
360080e500017e43c00000fbb524cc110 dm-12 AIX     ,VDASD           
size=250G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
  `- 0:0:4:0 sdd 8:48 active ready running
360080e500017e43c00000fb8524cc0e3 dm-10 AIX     ,VDASD           
size=250G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
  `- 0:0:2:0 sdb 8:16 active ready running
360080e500018110000000a97524cd2db dm-13 AIX     ,VDASD           
size=250G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='service-time 0' prio=1 status=active
  `- 0:0:5:0 sde 8:64 active ready running
</cli>

yum install sysfsutils

===== FC adapter list WWN =====

<cli prompt='#'>
# cat /sys/class/fc_host/host*/port_name
</cli>

===== Discover new devices =====

Install sg3_utils and lsscsi package. 

<cli prompt='#'>
[root@fedora01 ~]# /usr/bin/rescan-scsi-bus.sh -l
Host adapter 0 (mptspi) found.
Scanning SCSI subsystem for new devices
Scanning host 0 for  SCSI target IDs  0 1 2 3 4 5 6 7, LUNs  0 1 2 3 4 5 6 7 
</cli>

<cli prompt='#'>
[root@fedora01 ~]# lsscsi
[0:0:0:0]    disk    VMware   Virtual disk     1.0   /dev/sda
[0:0:1:0]    disk    VMware   Virtual disk     1.0   /dev/sdb 
</cli>

If rescan not working (for all linux and also Ubuntu) try:
<cli prompt='#'>
[root@ubuntu ~]# ls /sys/class/scsi_host/host*/scan
[root@ubuntu ~]# echo "- - -" > /sys/class/scsi_host/host0/scan
[root@ubuntu ~]# echo "- - -" > /sys/class/scsi_host/host1/scan
</cli>

<code>
for i in $(ls /sys/class/scsi_host/host*/scan); do echo "- - -" > $i; done
</code>

You can get the Fiber Channel addresses of the HBAs by typing the following commands:
<cli prompt='#'>
# systool -c fc_host -v
</cli>

Type the following command to determine the fibre channel target WWN:
<cli prompt='#'>
# systool -c fc_transport -v
</cli>

You will get node name (FC WWN) and port name of the storage processor port. Type the following command, to determine the mapping between SCSI HBTL addresses and the disks:
<cli prompt='#'>
# sg_map -x
</cli>

<cli prompt='#'>
[root@fedora22 multipath]# dmsetup ls
fedora-swap	(253:0)
fedora-root	(253:1)
</cli>

<cli prompt='#'>
[root@fedora22 multipath]# lsscsi 
[0:0:1:0]    disk    AIX      VDASD            0001  /dev/sda 
[0:0:2:0]    cd/dvd  AIX      VOPTA                  /dev/sr0 
</cli>

<cli prompt='#'>
[root@fedora22 multipath]# lsblk 
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0   50G  0 disk 
├─sda1            8:1    0    4M  0 part 
├─sda2            8:2    0  500M  0 part /boot
└─sda3            8:3    0 49.5G  0 part 
  ├─fedora-swap 253:0    0    2G  0 lvm  [SWAP]
  └─fedora-root 253:1    0 47.5G  0 lvm  /
sr0              11:0    1 1024M  0 rom  
</cli>

===== Remove a device =====

If you want to remove a device for example a disk /dev/mapper/mapthb, remove his multipath device using:
<cli prompt='#'>
[root@fedora22 multipath]# dmsetup remove mpathb
</cli>

===== Multipathing configuration =====

Configure
<cli prompt='#'>
[root@gpfs01 ~]# multipath -t > /etc/multipath.conf
[root@gpfs01 ~]# systemctl enable multipathd.service
[root@gpfs01 ~]# systemctl start multipathd.service
</cli>

Rescan
<cli prompt='#'>
[root@gpfs01 ~]# for i in $(ls /sys/class/scsi_host/host*/scan); do echo "- - -" > $i; done
[root@gpfs01 ~]# lsscsi
[0:2:0:0]    disk    IBM      ServeRAID M1115  2.13  /dev/sda
[0:2:1:0]    disk    IBM      ServeRAID M1115  2.13  /dev/sdb
[1:0:0:0]    cd/dvd  IMM      Virtual Media    0325  /dev/sr1
[2:0:0:0]    cd/dvd  IBM SATA DEVICE 81Y3676   IBD1  /dev/sr0
[8:0:0:0]    disk    IBM      2145             0000  /dev/sdc
[8:0:1:0]    disk    IBM      2145             0000  /dev/sdd
[9:0:2:0]    disk    IBM      2145             0000  /dev/sde
[9:0:3:0]    disk    IBM      2145             0000  /dev/sdf
[root@gpfs01 ~]# multipath -ll
mpatha (36005076300810163a000000000000057) dm-5 IBM     ,2145
size=8.0G features='1 queue_if_no_path' hwhandler='0' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 9:0:3:0 sdf 8:80 active ready running
| `- 8:0:1:0 sdd 8:48 active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 8:0:0:0 sdc 8:32 active ready running
  `- 9:0:2:0 sde 8:64 active ready running
</cli>

===== Multipathing error =====

==== Path offline ====

<cli prompt='#'>
[root@lnxa087 scripts]# /usr/sbin/multipath -ll
mpatha (36005076801818664680000000000062d) dm-0 IBM     ,2145
size=40G features='1 queue_if_no_path' hwhandler='0' wp=rw
|-+- policy='service-time 0' prio=0 status=enabled
| |- 1:0:2:0 sdb 8:16  failed faulty offline
| |- 2:0:2:0 sdh 8:112 failed faulty offline
| |- 3:0:2:0 sde 8:64  failed faulty offline
| `- 4:0:2:0 sdg 8:96  failed faulty offline
`-+- policy='service-time 0' prio=10 status=active
  |- 1:0:0:0 sda 8:0   active ready running
  |- 2:0:0:0 sdc 8:32  active ready running
  |- 3:0:0:0 sdd 8:48  active ready running
  `- 4:0:0:0 sdf 8:80  active ready running
[root@lnxa087 scripts]# pvs
  /dev/sdb: open failed: No such device or address
  /dev/sde: open failed: No such device or address
  /dev/sdg: open failed: No such device or address
  /dev/sdh: open failed: No such device or address
  PV                  VG     Fmt  Attr PSize  PFree
  /dev/mapper/mpatha3 centos lvm2 a--  38.99g    0
</cli>

First try to rescan:
<cli prompt='#'>
[root@lnxa087 scripts]# for i in $(ls /sys/class/scsi_host/host*/scan); do echo "- - -" > $i; done
</cli>

If not success, check adapter status (required **sysfsutils** package)
<cli prompt='#'>
[root@lnxa087 etc]# systool -c fc_host -v
Class = "fc_host"

  Class Device = "host1"
  Class Device path = "/sys/devices/vio/30000004/host1/fc_host/host1"
    dev_loss_tmo        = "300"
    fabric_name         = "0xc0507608249e00ac"
    issue_lip           = <store method only>
    maxframe_size       = "2048 bytes"
    node_name           = "0xc0507608249e00ac"
    port_id             = "0xbf1b13"
    port_name           = "0xc0507608249e00ac"
    port_state          = "Online"
    port_type           = "NPIV VPORT"
    speed               = "8 Gbit"
    supported_classes   = "Class 2, Class 3"
    tgtid_bind_type     = "wwpn (World Wide Port Name)"
    uevent              =

    Device = "host1"
    Device path = "/sys/devices/vio/30000004/host1"
      uevent              = "DEVTYPE=scsi_host"
...
</cli>

If adapters OK, the remove failed paths:
<cli prompt='#'>
[root@lnxa087 etc]# rescan-scsi-bus.sh -r
</cli>

Rescan
<cli prompt='#'>
[root@lnxa087 etc]# sg_map -x
/dev/sg1  1 0 0 0  0  /dev/sda
/dev/sg3  2 0 0 0  0  /dev/sdc
/dev/sg4  3 0 0 0  0  /dev/sdd
/dev/sg6  4 0 0 0  0  /dev/sdf
[root@lnxa087 scripts]# for i in $(ls /sys/class/scsi_host/host*/scan); do echo "- - -" > $i; done
</cli>

Check again:
<cli prompt='#'>
[root@lnxa087 etc]# [root@lnxa087 etc]# sg_map -x
/dev/sg0  1 0 2 0  0  /dev/sdb
/dev/sg1  1 0 0 0  0  /dev/sda
/dev/sg2  2 0 2 0  0  /dev/sde
/dev/sg3  2 0 0 0  0  /dev/sdc
/dev/sg4  3 0 0 0  0  /dev/sdd
/dev/sg5  3 0 2 0  0  /dev/sdg
/dev/sg6  4 0 0 0  0  /dev/sdf
/dev/sg7  4 0 2 0  0  /dev/sdh
[root@lnxa087 etc]# /usr/sbin/multipath -ll
mpatha (36005076801818664680000000000062d) dm-0 IBM     ,2145
size=40G features='1 queue_if_no_path' hwhandler='0' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 1:0:2:0 sdb 8:16  active ready running
| |- 2:0:2:0 sde 8:64  active ready running
| |- 3:0:2:0 sdg 8:96  active ready running
| `- 4:0:2:0 sdh 8:112 active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 1:0:0:0 sda 8:0   active ready running
  |- 2:0:0:0 sdc 8:32  active ready running
  |- 3:0:0:0 sdd 8:48  active ready running
  `- 4:0:0:0 sdf 8:80  active ready running
</cli>

==== Path missing ====

<cli prompt='$'>
[root@lnxb603n /root]$ multipath -ll
mpathj (3600507680181866468000000000012fd) dm-5 IBM,2145
size=40G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 1:0:0:1 sdb 8:16  active ready running
| `- 4:0:0:1 sdn 8:208 active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 1:0:3:1 sdd 8:48  active ready running
  `- 4:0:3:1 sdp 8:240 active ready running
  
[root@lnxb603n /root]$ rescan-scsi-bus.sh

[root@lnxb603n /root]$ for i in $(ls /sys/class/scsi_host/host*/scan); do echo "- - -" > $i; done

[root@lnxb603n /root]$ multipath -ll
mpathj (3600507680181866468000000000012fd) dm-5 IBM,2145
size=40G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 1:0:0:1 sdb 8:16  active ready running
| `- 4:0:0:1 sdn 8:208 active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 1:0:3:1 sdd 8:48  active ready running
  `- 4:0:3:1 sdp 8:240 active ready running

[root@lnxb603n /root]$ /sbin/mpathconf --find_multipaths y

[root@lnxb603n /root]$ multipath -v3

[root@lnxb603n /root]$ multipath -ll
mpathj (3600507680181866468000000000012fd) dm-5 IBM,2145
size=40G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 1:0:0:1 sdb 8:16  active ready running
| |- 2:0:0:1 sdf 8:80  active ready running
| |- 3:0:0:1 sdj 8:144 active ready running
| `- 4:0:0:1 sdn 8:208 active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 1:0:3:1 sdd 8:48  active ready running
  |- 2:0:3:1 sdh 8:112 active ready running
  |- 3:0:3:1 sdl 8:176 active ready running
  `- 4:0:3:1 sdp 8:240 active ready running
</cli>

==== Device not found ====

Device not discover on a new IOgroup
  Do a deeper rescan to login to the new SVC nodes
<cli prompt='#'>
for i in $(ls /sys/class/scsi_host/host*/scan); do echo "- - -" > $i; done
</cli>

==== Connections to VIOS ====

<cli prompt='#'>
[root@lnx001 /root/scripts]$ systool -c scsi_host -v
Class = "scsi_host"

  Class Device = "host0"
  Class Device path = "/sys/devices/vio/30000002/host0/scsi_host/host0"
    active_mode         = "Initiator"
    can_queue           = "100"
    cmd_per_lun         = "16"
    config              =
    eh_deadline         = "off"
    host_busy           = "0"
    host_reset          = <store method only>
    mad_version         = "1"
    nr_hw_queues        = "1"
    os_type             = "3"
    partition_name      = "VIOS01"
    partition_number    = "2"
    proc_name           = "ibmvscsi"
    prot_capabilities   = "0"
    prot_guard_type     = "0"
    scan                = <store method only>
    sg_prot_tablesize   = "0"
    sg_tablesize        = "128"
    srp_version         = "16.a"
    state               = "running"
    supported_mode      = "Initiator"
    uevent              =
    unchecked_isa_dma   = "0"
    unique_id           = "0"
    use_blk_mq          = "1"
    vhost_loc           = "U9009.22G.xxxxxxx-V20-C2-T1"
    vhost_name          = "vhost13"

    Device = "host0"
    Device path = "/sys/devices/vio/30000002/host0"
      uevent              = "DEVTYPE=scsi_host"


  Class Device = "host1"
  Class Device path = "/sys/devices/vio/30000003/host1/scsi_host/host1"
    active_mode         = "Initiator"
    can_queue           = "100"
    capabilities        = "105d"
    cmd_per_lun         = "16"
    device_name         = "vfchost21"
    drc_name            = "U9009.22G.78D0270-V2-C38"
    eh_deadline         = "off"
    host_busy           = "0"
    host_reset          = <store method only>
    log_level           = "2"
    npiv_version        = "2"
    nr_hw_queues        = "1"
    nr_scsi_channels    = "1"
    partition_name      = "VIOS01"
    port_loc_code       = "U78D3.001.xxxxxxx-P1-C10-T2"
    proc_name           = "ibmvfc"
    prot_capabilities   = "0"
    prot_guard_type     = "0"
    scan                = <store method only>
    sg_prot_tablesize   = "0"
    sg_tablesize        = "128"
    state               = "running"
    supported_mode      = "Initiator"
    trace               = "▒G{e"
    uevent              =
    unchecked_isa_dma   = "0"
    unique_id           = "1"
    use_blk_mq          = "1"

    Device = "host1"
    Device path = "/sys/devices/vio/30000003/host1"
      uevent              = "DEVTYPE=scsi_host"
</cli>