Multipath troubleshooting

Use this information to help pinpoint potential causes for multipath failures.

Display multipath information (FC and iSCSI)

Display multipath information, using the sudo multipath -ll command.

mpathb (3600507680283851530000000000000a6) dm-0 IBM,2145
size=1.0G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| `- 3:0:0:0 sda 8:0  active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  `- 2:0:0:0 sdb 8:16 active ready running

Display device attachment

Display device attachment information, using the sudo lsblk command.

NAME     MAJ:MIN RM SIZE RO TYPE  MOUNTPOINT
sda        8:0    0   1G  0 disk  
`-mpathb 253:0    0   1G  0 mpath /var/lib/kubelet/pods/c9fee230-6227-11ea-a0b6-52fdfc072182/volumes/kubernetes.io~csi/pvc-32a7e21b-6227-11ea-a0b6-52fdfc
sdb        8:16   0   1G  0 disk  
`-mpathb 253:0    0   1G  0 mpath /var/lib/kubelet/pods/c9fee230-6227-11ea-a0b6-52fdfc072182/volumes/kubernetes.io~csi/pvc-32a7e21b-6227-11ea-a0b6-52fdfc
vda      252:0    0  31G  0 disk  
|-vda1   252:1    0   1M  0 part  
|-vda2   252:2    0   1G  0 part  /boot
`-vda3   252:3    0  30G  0 part  /sysroot

To display device attachment information, together with SCSI ID information, use the sudo lsblk -S command.

NAME HCTL       TYPE VENDOR   MODEL             REV TRAN
sda  3:0:0:0    disk IBM      2145             0000 iscsi
sdb  2:0:0:0    disk IBM      2145             0000 iscsi

Check for multipath daemon availability (FC and iSCSI)

Check for multipath daemon availability, using the systemctl status multipathd command.

multipathd.service - Device-Mapper Multipath Device Controller
   Loaded: loaded (/usr/lib/systemd/system/multipathd.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2020-03-09 16:28:37 UTC; 22min ago
 Main PID: 1235 (multipathd)
   Status: "up"
    Tasks: 7
   Memory: 14.1M
      CPU: 131ms
   CGroup: /system.slice/multipathd.service
           └─1235 /sbin/multipathd -d -s

Check for iSCSI daemon availability

Check for iSCSI daemon availability, using the systemctl status iscsid command.

iscsid.service - Open-iSCSI
   Loaded: loaded (/usr/lib/systemd/system/iscsid.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2020-03-09 16:28:37 UTC; 22min ago
     Docs: man:iscsid(8)
           man:iscsiadm(8)
 Main PID: 1440 (iscsid)
   Status: "Ready to process requests"
    Tasks: 1 (limit: 26213)
   Memory: 4.7M
      CPU: 27ms
   CGroup: /system.slice/iscsid.service
           └─1440 /usr/sbin/iscsid -f