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====== LVM howto ======

http://www.datadisk.co.uk/html_docs/redhat/rh_lvm.htm

http://www.voleg.info/linux-mirror-system-disk.html

https://www.thegeekdiary.com/centos-rhel-7-how-to-create-and-remove-the-lvm-mirrors-using-lvconvert/

http://www.voleg.info/linux-mirror-system-disk.html

===== Disk cloning RHEL9 =====

For RHEL9 and higher

After booting on a clone, the server will start in single mode user. No pv or vg is visible

You have to update the file **/etc/lvm/devices/system.devices** to match the disk WWN
<cli prompt='#'>
[root@rhtest ~]# multipath -ll
mpatha (36005076xxxxxxxxxxx000000000017b9) dm-0 IBM,2145
size=60G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw
</cli>

Or use the command
<cli prompt='#'>
lvmdevices --update
</cli>

<cli prompt='#'>
[root@rhtest ~]# cat /etc/lvm/devices/system.devices
# LVM uses devices listed in this file.
# Created by LVM command vgimportdevices pid 65293 at Wed May 21 10:23:35 2025
HOSTNAME=rhtest
VERSION=1.1.10
IDTYPE=mpath_uuid IDNAME=part3-mpath-36005076xxxxxxxxxxx00000000001616 DEVNAME=/dev/mapper/mpatha3 PVID=JzZ6Nf4VUZFbBcNle1TX9miPydVISnYT
</cli>

Also update the multipathing binding if you want to change order
<cli prompt='#'>
[root@rhtest ~]# cat /etc/multipath/bindings
# Multipath bindings, Version : 1.0
# NOTE: this file is automatically maintained by the multipath program.
# You should not need to edit this file in normal circumstances.
#
# Format:
# alias wwid
#
mpatha 36005076xxxxxxxxxxx00000000001616 
mpathb 36005076xxxxxxxxxxx000000000017b9
</cli>

After updating all files, import VG devices. 
  * to import all pv, vg (will only add the multipath map): vgimportdevices -a 
  * If only some of the disks contain PV’s (for each to be used device) to be used by this system run: lvmdevices --adddev [device name] 
  For example: lvmdevices --adddev /dev/mapper/mpathc  



Now reboot. Everything is OK

  * By default in a newly installed RHEL9 system 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.


===== LVM import same VGname =====

Here as you can see **Not using device**, it's a duplicate VG, so not possible to import the VG
<cli prompt='#'>
[root@rhtest ~]# pvscan
  WARNING: Not using device /dev/sdc1 for PV GuRFbq-coDt-Bg6l-lraR-JYRZ-zbQx-8mknGe.
  WARNING: Not using device /dev/sdd3 for PV m8MZp2-r66w-lR11-ilJ7-bjPS-zopv-BFGFuc.
  WARNING: PV GuRFbq-coDt-Bg6l-lraR-JYRZ-zbQx-8mknGe prefers device /dev/sdb1 because device is used by LV.
  WARNING: PV m8MZp2-r66w-lR11-ilJ7-bjPS-zopv-BFGFuc prefers device /dev/sda3 because device is used by LV.
  PV /dev/sdb1   VG rhel_redhat-data   lvm2 [<30.00 GiB / 1020.00 MiB free]
  PV /dev/sda3   VG rhel_redhattest1   lvm2 [22.41 GiB / 0    free]
  Total: 2 [<52.41 GiB] / in use: 2 [<52.41 GiB] / in no VG: 0 [0   ]
</cli>

To import the VG, you have to rename it during import like this
<cli prompt='#'>
[root@rhtest ~]# vgimportclone -n vg01 /dev/sdc1
[root@rhtest ~]# vgimportclone -n vg02 /dev/sdd3
[root@rhtest ~]# vgs
  VG               #PV #LV #SN Attr   VSize   VFree
  rhel_redhat-data   1   1   0 wz--n- <30.00g 1020.00m
  rhel_redhattest1   1   2   0 wz--n-  22.41g       0
  vg01               1   1   0 wz--n- <30.00g 1020.00m
  vg02               1   2   0 wz--n-  22.41g       0
[root@rhtest ~]# lvs
  LV               VG               Attr       LSize   Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  rhel_redhat-data rhel_redhat-data -wi-ao----  29.00g
  root             rhel_redhattest1 -wi-ao---- <20.01g
  swap             rhel_redhattest1 -wi-ao----   2.40g
  rhel_redhat-data vg01             -wi-------  29.00g
  root             vg02             -wi------- <20.01g
  swap             vg02             -wi-------   2.40g
</cli>

Now you're able to mount the filesystems, just enable first the 2 new VGs
<cli prompt='#'>
[root@rhtest ~]# vgchange -ay vg01
[root@rhtest ~]# vgchange -ay vg02
</cli>

Check filesystem type
<cli prompt='#'>
[root@rhtest ~]# lsblk -o FSTYPE,MOUNTPOINT,NAME /dev/sdd
FSTYPE      MOUNTPOINT NAME
                       sdd
vfat                   ├─sdd1
xfs                    ├─sdd2
LVM2_member            └─sdd3
xfs         /            ├─rhel_redhattest1-root
swap        [SWAP]       └─rhel_redhattest1-swap
</cli>


Check the filesystem using xfs_repair for xfs and fsck for ext4
<cli prompt='#'>
[root@rhtest ~]# xfs_repair -v /dev/mapper/vg01-rhel_redhat--data
Phase 1 - find and verify superblock...
        - block cache size set to 369264 entries
Phase 2 - using internal log
        - zero log...
zero_log: head block 25428 tail block 25424
ERROR: The filesystem has valuable metadata changes in a log which needs to
be replayed.  Mount the filesystem to replay the log, and unmount it before
re-running xfs_repair.  If you are unable to mount the filesystem, then use
the -L option to destroy the log and attempt a repair.
Note that destroying the log may cause corruption -- please attempt a mount
of the filesystem before doing this.
</cli>

If error to mount, I've first done a : xfs_repair -L <LV>

Mount the filesystem
<cli prompt='#'>
[root@rhtest ~]# mount -t xfs /dev/mapper/vg02-root /mnt3
mount: /mnt3: wrong fs type, bad option, bad superblock on /dev/mapper/vg02-root, missing codepage or helper program, or other error.
[root@rhtest ~]# mount -o nouuid /dev/mapper/vg02-root /mnt3
</cli>

===== Create a new filesystem =====

==== Discover disk ====

Create a new disk for linux, rescan and create a partition type 8e00 (LVM) using **gdisk**
<cli prompt='#'>
[root@lnxa081 centos_75]# rescan-scsi-bus.sh -a

[root@lnxa081 centos_75]# gdisk /dev/mapper/mpathb
GPT fdisk (gdisk) version 0.8.6

Partition table scan:
  MBR: not present
  BSD: not present
  APM: not present
  GPT: not present

Creating new GPT entries.

Command (? for help): n
Partition number (1-128, default 1):
First sector (34-83886046, default = 2048) or {+-}size{KMGTP}:
Last sector (2048-83886046, default = 83886046) or {+-}size{KMGTP}:
Current type is 'Linux filesystem'
Hex code or GUID (L to show codes, Enter = 8300): 8e00
Changed type of partition to 'Linux LVM'

Command (? for help): w

Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING
PARTITIONS!!

Do you want to proceed? (Y/N): y
OK; writing new GUID partition table (GPT) to /dev/mapper/mpathb.
Warning: The kernel is still using the old partition table.
The new table will be used at the next reboot.
The operation has completed successfully.
[root@lnxa081 centos_75]# gdisk -l /dev/mapper/mpathb
GPT fdisk (gdisk) version 0.8.6

Partition table scan:
  MBR: protective
  BSD: not present
  APM: not present
  GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/mapper/mpathb: 83886080 sectors, 40.0 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 6E544892-1B5E-40AA-8551-00D674313F21
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 83886046
Partitions will be aligned on 2048-sector boundaries
Total free space is 2014 sectors (1007.0 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1            2048        83886046   40.0 GiB    8E00  Linux LVM
</cli>

==== Create PV ====

Create a VG, and LV, filesystem:
<cli prompt='#'>
[root@lnxa081 centos_75]# ls /dev/mapper/mpathb*
/dev/mapper/mpathb
[root@lnxa081 centos_75]# partprobe -s
[root@lnxa081 centos_75]# ls /dev/mapper/mpathb*
/dev/mapper/mpathb  /dev/mapper/mpathb1
[root@lnxa081 centos_75]# pvcreate /dev/mapper/mpathb1
  Physical volume "/dev/mapper/mpathb1" successfully created.
[root@lnxa081 centos_75]# pvs
  PV                  VG     Fmt  Attr PSize   PFree
  /dev/mapper/mpathb1 datavg lvm2 a--  <40.00g <40.00g
</cli>

<cli prompt='#'>
[root@lnxa081 ~]#  pvs   --segments  -o +lv_name,lv_size
  PV                    VG             Fmt  Attr PSize   PFree    Start   SSize   LV              LSize
  /dev/mapper/mpathwp1  vg_container01 lvm2 a--    5.00t    5.00t       0 1310719                      0
  /dev/mapper/mpathxp1  vg_container01 lvm2 a--    5.00t    4.00t       0  262146 lv_container001  11.00t
  /dev/mapper/mpathxp1  vg_container01 lvm2 a--    5.00t    4.00t  262146 1048573                      0
  /dev/mapper/mpathyp1  vg_container01 lvm2 a--    5.00t       0        0 1310719 lv_container001  11.00t
  /dev/mapper/mpathzp1  vg_container01 lvm2 a--    5.00t       0        0 1310719 lv_container001  11.00t
</cli>

==== Create VG ====

<cli prompt='#'>
[root@lnxa081 centos_75]# vgcreate datavg /dev/mapper/mpathb1
  Volume group "datavg" successfully created
[root@lnxa081 centos_75]# vgs
  VG     #PV #LV #SN Attr   VSize   VFree
  datavg   1   0   0 wz--n- <40.00g <40.00g
</cli>

==== Create a LV ====

<cli prompt='#'>
[root@lnxa081 centos_75]# lvcreate -n postgres1lv -L20G datavg
  Logical volume "postgres1lv" created.
[root@lnxa081 centos_75]# lvs
  LV          VG     Attr       LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
  postgres1lv datavg -wi-a----- 20.00g
</cli>

==== Create a FS ====

Filesystems most used type are: xfs, ext4, and coming btrfs
<cli prompt='#'>
[root@lnxa081 centos_75]# mkfs.xfs /dev/mapper/datavg-postgres1lv
meta-data=/dev/mapper/datavg-postgres1lv isize=512    agcount=16, agsize=327680 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0, sparse=0
data     =                       bsize=4096   blocks=5242880, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal log           bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
[root@lnxa081 centos_75]# cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Fri May 18 07:49:08 2018
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=fe7f5254-1302-4bd5-8e3e-1a6046ce2943 /                       btrfs   subvol=root     0 0
UUID=39651e3e-f8a3-4e46-ab7f-6b3ea7bb5991 /boot                   xfs     defaults        0 0
UUID=fe7f5254-1302-4bd5-8e3e-1a6046ce2943 /home                   btrfs   subvol=home     0 0
UUID=58d659e7-72ff-4434-8803-7e4a5df78b91 swap                    swap    defaults        0 0
/dev/mapper/datavg-postgres1lv            /postgres1              xfs     defaults        0 0
[root@lnxa081 centos_75]# mkdir /postgres1
[root@lnxa081 centos_75]# mount /postgres1
[root@lnxa081 centos_75]# df -h | grep post
/dev/mapper/datavg-postgres1lv   20G   33M   20G   1% /postgres1
</cli>

==== Extend a FS ====

Extend XFS filesystem using **xfs_growfs**

In one command:
<cli prompt='#'>
[root@lnxa081 centos_75]# lvextend -L +1G --resizefs /dev/mapper/datavg-postgres1lv
</cli>

Or 2 commands
<cli prompt='#'>
[root@lnxa081 centos_75]# lvextend -L +1G /dev/mapper/datavg-postgres1lv
  Size of logical volume datavg/postgres1lv changed from 20.00 GiB (5120 extents) to 21.00 GiB (5376 extents).
  Logical volume datavg/postgres1lv successfully resized.
[root@lnxa081 centos_75]# xfs_growfs -d  /dev/mapper/datavg-postgres1lv
meta-data=/dev/mapper/datavg-postgres1lv isize=512    agcount=16, agsize=327680 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=1        finobt=0 spinodes=0
data     =                       bsize=4096   blocks=5242880, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=1
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 5242880 to 5505024
[root@lnxa081 centos_75]# df -h | grep post
/dev/mapper/datavg-postgres1lv   20G   33M   20G   1% /postgres1
</cli>

===== Filesystem reserved blocks percentage =====

==== EXT filesystems ====

Change the default reserved blocks percentage cache size for filesystems, to use more space (default value is 5%):
<cli prompt='#'>
[root@rh-tsm ~]# tune2fs -l /dev/mapper/TSMDB-TSMDB02_lv
tune2fs 1.42.9 (28-Dec-2013)
Filesystem volume name:   <none>
Last mounted on:          /TSMDATABASE/DATA/db2
Filesystem UUID:          e52277be-f820-4906-b6a3-1b30e0e88934
Filesystem magic number:  0xEF53
Filesystem revision :    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         unsigned_directory_hash
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              8126464
Block count:              32505856
Reserved block count #:   1625292
Free blocks:              6970825
Free inodes:              8126353
First block:              0
Block size:               4096
Fragment size:            4096
Group descriptor size:    64
Reserved GDT blocks:      1024
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
RAID stride:              8
RAID stripe width:        8
Flex block group size:    16
Filesystem created:       Mon Jan 23 14:14:45 2017
Last mount time:          Mon Jan 23 15:03:52 2017
Last write time:          Mon Jan 23 15:03:52 2017
Mount count:              2
Maximum mount count:      -1
Last checked:             Mon Jan 23 14:14:45 2017
Check interval:           0 (<none>)
Lifetime writes:          97 GB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
Default directory hash:   half_md4
Directory Hash Seed:      d81553db-6a9f-42de-978d-36c420a52b9f
Journal backup:           inode blocks
[root@rh-tsm ~]# tune2fs -m 3 /dev/mapper/TSMDB-TSMDB02_lv
tune2fs 1.42.9 (28-Dec-2013)
Setting reserved blocks percentage to 3% (975175 blocks)
</cli>

==== XFS filesystems ====

To see the number of reserved blocks on a mounted XFS file system:
<cli prompt='#'>
# xfs_io -x -c "resblks" /root/test
</cli>

We can use this command to change the reserved number of blocks on a mounted XFS file system (replace <blocks> with an integer number):
<cli prompt='#'>
# xfs_io -x -c "resblks <blocks>" /root/test
</cli>

To compute the percentage of reserved blocks, one must get the total number of blocks in the file system by multiplying the agcount and agsize numbers together.   Those values are obtained via this command:
<cli prompt='#'>
# xfs_info /root/test
meta-data=/dev/vda2              isize=256    agcount=4, agsize=6400 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=0        finobt=0
data     =                       bsize=4096   blocks=25600, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
log      =internal               bsize=4096   blocks=853, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
</cli>
The reserved block percentage would be:  100 * "reserved blocks" / (agsize * agcount)

Users may be surprised to see values less than 1%, whereas older file systems typically defaulted to 5%. 
    * We default to 5% or 8192 fsbs of space reserved, whichever is
    * smaller.  This is intended to cover concurrent allocation
    * transactions when we initially hit enospc. These each require a 4
    * block reservation. Hence by default we cover roughly 2000 concurrent
    * allocation reservations.

===== Create mirror LV =====

==== LVM Mirroring Method ====

lvconvert with option -m1 for mirror and -m0 to remove a mirror copy

Create a mirror LV
<cli prompt='#'>
# lvconvert -m1 datavg/my_lv
</cli>

Check synchronization status
<cli prompt='#'>
# lvs -a -o name,copy_percent,devices datavg
  LV               Copy%  Devices
  my_lv            100.00 my_lv_rimage_0(0),my_lv_rimage_1(0)
  [my_lv_rimage_0]        /dev/sda1(1)
  [my_lv_rimage_1]        /dev/sdb1(1)
  [my_lv_rmeta_0]         /dev/sda1(0)
  [my_lv_rmeta_1]         /dev/sdb1(0)
  
# lvs --all --segments -o +devices
  LV                VG     Attr       #Str Type   SSize  Devices
  root              centos -wi-ao----    1 linear 17.47g /dev/sda2(512)
  swap              centos -wi-ao----    1 linear  2.00g /dev/sda2(0)
  testlv            datavg rwi-aor---    2 raid1   1.00g testlv_rimage_0(0),testlv_rimage_1(0)
  [testlv_rimage_0] datavg iwi-aor---    1 linear  1.00g /dev/sdb(0)
  [testlv_rimage_1] datavg iwi-aor---    1 linear  1.00g /dev/sdc(1)
  [testlv_rmeta_0]  datavg ewi-aor---    1 linear  4.00m /dev/sdb(256)
  [testlv_rmeta_1]  datavg ewi-aor---    1 linear  4.00m /dev/sdc(0)
</cli>

Once synchronized, you can remove one copy you have to specify the disk to remove
<cli prompt='#'>
# lvconvert -m0 datavg/my_lv /dev/sda1
# lvs -a -o name,copy_percent,devices datavg
  LV    Copy%  Devices
  datalv        /dev/sdb1(1)
</cli>

==== Other functions ====

To Repair  a mirror after suffering a disk failure.
<cli prompt='#'>
# lvconvert --repair
</cli> 

To Merges  a snapshot into its origin volume.
<cli prompt='#'>
# lvconvert --merge 
</cli>

To Create  a  snapshot from existing logical volume using another existing logical volume as its origin                
<cli prompt='#'>
# lvconvert -s
# lvconvert --snapshot
</cli>                

To split off mirror images to form a new logical volume
<cli prompt='#'>
# lvconvert --splitmirrors Images
</cli>

==== LVM pvmove Mirroring Method ====

Instead using ‘lvconvert’ mirroring command, we use here ‘pvmove‘ command with option ‘-n‘ (logical volume name) method to mirror data between two devices.
<cli prompt='#'>
# pvmove -n /dev/datavg/data1lv /dev/vdb1 /dev/sda1
</cli>
The command is one of the simplest way to mirror the data between two devices, but in real environment Mirroring is used more often than pvmove.

==== Filestems list ====

List filesystems type
<cli prompt='#'>
manu-opensuse:~ # df -Th
Filesystem                      Type      Size  Used Avail Use% Mounted on
devtmpfs                        devtmpfs  7.8G  4.0K  7.8G   1% /dev
tmpfs                           tmpfs     7.8G  487M  7.3G   7% /dev/shm
tmpfs                           tmpfs     7.8G  1.9M  7.8G   1% /run
tmpfs                           tmpfs     7.8G     0  7.8G   0% /sys/fs/cgroup
/dev/sda3                       btrfs      40G   35G  5.1G  88% /
/dev/sda1                       vfat      511M  8.4M  503M   2% /boot/efi
/dev/sda3                       btrfs      40G   35G  5.1G  88% /boot/grub2/i386-pc
/dev/sda4                       xfs        25G   18G  7.4G  71% /home
/dev/sda3                       btrfs      40G   35G  5.1G  88% /root
/dev/sda3                       btrfs      40G   35G  5.1G  88% /.snapshots
/dev/mapper/libraryvg-uncryptlv ext4      192G  175G  8.6G  96% /library/uncrypt
</cli>

List only disks and partitions, with UUID
<cli prompt='#'>
manu-opensuse:~ # lsblk -f
NAME                    FSTYPE LABEL UUID                                   FSAVAIL FSUSE% MOUNTPOINT
sda                                                                                             
├─sda1                  vfat         F926-FC70                               502.7M     2% /boot/efi
├─sda2                  ext3         a2e132cf-d69c-448c-bc59-9e833bebb95c                  
├─sda3                  btrfs        a3da64e9-f198-4cb2-adcd-01ec0541cba9        5G    87% /
├─sda4                  xfs          4c91d4e3-89f7-4b17-9507-84b17c69d777      7.3G    71% /home
├─sda5                  swap         859cf5c6-a1ba-4711-98b2-387b8c2bd860                  [SWAP]
└─sda6                  LVM2_member  1z8s8i-WQL7-yutq-VKYE-cbBD-p1ZB-3dCuwo                
  ├─libraryvg-vmlv      ext4         35bfc2a9-a3c0-4eee-82a1-1f62ca52aad7      9.3G    88% /virtual_vm
  ├─libraryvg-uncryptlv ext4         4feeb184-a8a2-44a2-ac49-ade56c01853a      8.6G    91% /library/uncrypt
  └─libraryvg-cryptlv   crypto_LUKS  5667183b-30ad-4bba-9c00-df9142079076                  
</cli>

For persitent mount, you can use also UUID
<cli prompt='#'>
UUID=a3da64e9-f198-4cb2-adcd-01ec0541cba9  /              btrfs  defaults                      0  0
UUID=a3da64e9-f198-4cb2-adcd-01ec0541cba9  /.snapshots    btrfs  subvol=/@/.snapshots          0  0
UUID=a3da64e9-f198-4cb2-adcd-01ec0541cba9  /var           btrfs  subvol=/@/var                 0  0
UUID=4c91d4e3-89f7-4b17-9507-84b17c69d777  /home          xfs    defaults                      0  0
UUID=859cf5c6-a1ba-4711-98b2-387b8c2bd860  swap           swap   defaults                      0  0
/dev/libraryvg/vmlv                        /virtual_vm    ext4   defaults                      0  2
</cli>

===== list PVID / VGID =====

the PVID and VGID of disk


===== Errors on LVM =====

==== Found duplicate PV (LVM) ====

LVM commands (such as vgs, lvchange, etc) display messages like this when trying to list VG or LV:
<cli prompt='#'>
Found duplicate PV GDjTZf7Y03GJHjteqOwrye2dcSCjdaUi: using /dev/dm-5 not /dev/sdd
Found duplicate PV GDjTZf7Y03GJHjteqOwrye2dcSCjdaUi: using /dev/emcpowerb not /dev/sde
Found duplicate PV GDjTZf7Y03GJHjteqOwrye2dcSCjdaUi: using /dev/sddlmab not /dev/sdf
</cli>

== Root Cause of Duplicate PV Warning ==

With a default configuration, LVM commands will scan for devices in /dev and check every resulting device for LVM metadata. This is caused by the default filter in the /etc/lvm/lvm.conf, which is as follows:
<cli prompt='#'>
filter = [ "a/.*/" ]
</cli>

When using Device Mapper Multipath or other multipath software such as EMC PowerPath or Hitachi Dynamic Link Manager (HDLM), each path to a particular logical unit number (LUN) is registered as a different SCSI device, such as /dev/sdb or /dev/sdc. The multipath software will then create a new device that maps to those individual paths, such as /dev/mapper/mpath1 or /dev/mapper/mpatha for Device Mapper Multipath, /dev/emcpowera for EMC PowerPath, or /dev/sddlmab for Hitachi HDLM. Since each LUN has multiple device nodes in /dev that point to the same underlying data, they all contain the same LVM metadata and thus LVM commands will find the same metadata multiple times and report them as duplicates. 

The filter you configure should include all devices that need to be checked for LVM metadata, such as the local hard drive with the root volume group on it and any multipathed devices. By rejecting the underlying paths to a multipath device (such as /dev/sdb, /dev/sdd, etc) you can avoid these duplicate PV warnings, since each unique metadata area will only be found once on the multipath device itself.
The following examples show filters that will avoid duplicate PV warnings due to multiple storage paths being available.

This filter accepts the second partition on the first hard drive (/dev/sda and any device-mapper-multipath devices, while rejecting everything else.
<cli prompt='#'>
filter = [ "a|/dev/sda2$|", "a|/dev/mapper/mpath.*|", "r|.*|" ]
</cli>

This filter accepts all HP SmartArray controllers and any EMC PowerPath devices.
<cli prompt='#'>
filter = [ "a|/dev/cciss/.*|", "a|/dev/emcpower.*|", "r|.*|" ]
</cli>

You can also test a filter on the fly, without modifying the /etc/lvm/lvm.conf file, by adding the
 --config argument to the LVM command, as in the following example.
<cli prompt='#'>
# lvs --config 'devices{ filter = [ "a|/dev/emcpower.*|", "r|.*|" ] }'
</cli>


Pb with duplicate PVs
<cli prompt='#'>
# vgchange -an
# vgimportclone --basevgname tsmdb01vg /dev/md124vgs
# vgscan
# vgchange -ay
</cli>



==== PV not create excluded by a filter ====

<cli prompt='#'>
[root@hrstsm01 multipath]# pvcreate /dev/mapper/mpathc
  Device /dev/mapper/mpathc excluded by a filter.

[root@hrstsm01 multipath]# dd if=/dev/zero of=/dev/mapper/mpathc bs=512 count=1
1+0 records in
1+0 records out
512 bytes (512 B) copied, 0.00945451 s, 54.2 kB/s

[root@hrstsm01 multipath]# pvcreate /dev/mapper/mpathc
  Device /dev/mapper/mpathc excluded by a filter.
</cli>

==== Force systemd to re-read fstab and create automount units ====

First:

# systemctl daemon-reload

followed by:

# systemctl restart remote-fs.target

or

# systemctl restart local-fs.target

==== How disable the devices file (RHEL9 an higher) ====

Disabling the devices file automatically enables the lvm.conf device filter.

Use LVM commands to control LVM device scanning. LVM commands interact with a file called the system.devices file, which lists the visible and usable devices. This feature is enabled by default in Red Hat Enterprise Linux 9.

You can enable Logical Volume Manager (LVM) to access and use all devices on the system, which overrides the restrictions caused by the devices listed in the system.devices

Add the line into **/etc/lvm/lvm.conf**
<code>
use_devicesfile=0
</code>

https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/9/html/configuring_and_managing_logical_volumes/limiting-lvm-device-visibility-and-usage_configuring-and-managing-logical-volumes
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