RHEL9 lvm2 cannot find imported VG physical volumes.

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux 8, 9, 10
  • lvm2-2.03.12-10.el8 and later

Issue

  • When trying to import foreign VG’s, while the physical volumes for the VG's are present in lsblk and lsscsi they are not found by LVM2.
  • pvscan --cache reports excluded by devices file (checking PVID).

Resolution

  • All Disks: If all disks on the RHEL server are PV’s to be used by this system then run the command vgimportdevices -a. If a LUN is multipathed vgimportdevices -a will only add the multipath map.

  • Some Disks: If only some of the disks contain PV’s to be used by this system run lvmdevices --adddev [device name] for each to be used device.
    For example: 

    lvmdevices --adddev /dev/mapper/mpathc

  • Shared Disks: If the volume group is a shared VG across all nodes in a Pacemaker cluster, see LVM-activate resource fails to start on passive node.

Root Cause

  • When use_devicesfile is enabled, LVM2 will use the /etc/lvm/devices/system.devices file to identify which disks are PV’s for this install. The /etc/lvm/lvm.conf filters are ignored. As the imported PV’s are not in this file LVM will not work with them.

  • If a RHEL8 system is upgraded to RHEL9 the /etc/lvm/devices/system.devices file does not exists LVM will run as if use_devicesfile = 0 is set and use the /etc/lvm/lvm.conf filters.

  • If the /etc/lvm/lvm.conf use_devicesfile parameter is set to 0. The /etc/lvm/devices/system.devices will not be used and the /etc/lvm/lvm.conf filters are used.

  • This is documented in the man pages for lvmdevices and vgimportdevices of the command help.

Diagnostic Steps

  • lsscsi and\or multipath -ll show the imported disks are attached.

    • lvm2 command pvs does not show the disks or multipath map.

    • Running pvscan –-cache [device_name] returns the error

      pvscan[xx] [device_name] excluded by devices file (checking PVID).

      For example the ldpath04 map below has been introduced and holds a to be imported
      VG.

        # multipath -ll 
ldbackup (36001405e46d9356d0074f878c5212909) dm-2 LIO-ORG,backup
size=1.0G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
`-+- policy='round-robin 0' prio=50 status=active
  `- 9:0:0:88 sdg 8:96 active ready running
ldpath04 (360014055acd50e8488f4a8da0ca0a3ce) dm-3 LIO-ORG,u10glv4
size=10G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
`-+- policy='round-robin 0' prio=50 status=active
  |- 6:0:0:4  sda 8:0  active ready running
  |- 7:0:0:4  sdc 8:32 active ready running
  `- 8:0:0:4  sde 8:64 active ready running

    • But the command pvs does not show /dev/mapper/rhpath04

      # pvs
 PV                   VG       Fmt  Attr PSize    PFree
 /dev/mapper/ldbackup ldbackup lvm2 a--  1020.00m    0 
 /dev/vda2            rhel     lvm2 a--    <9.00g    0

    • Neither does pvscan 

      # pvscan --cache 
  pvscan[68704] PV /dev/vda2 online.
  pvscan[68704] PV /dev/mapper/ldbackup online.

    • Trying to scan the device directly generates an error 

      # pvscan --cache /dev/mapper/ldpath04
  pvscan[68784] /dev/mapper/ldpath04 excluded by devices file (checking PVID).

    • Running lvmdevices shows devmapper/ldpath04 is missing. 

      lvmdevices
  Device /dev/mapper/ldbackup IDTYPE=mpath_uuid IDNAME=mpath-36001405e46d9356d0074f878c5212909 DEVNAME=/dev/mapper/ldbackup PVID=IuVSS4dZjE0WrmGlhFk3coYmxbV3pJqE
  Device /dev/vda2 IDTYPE=devname IDNAME=/dev/vda2 DEVNAME=/dev/vda2 PVID=VDoNwWJCHIuhc2j7eBwO1F66N2D57GYV PART=2
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