kernel-6.12.0-165.el10    BUILT: Fri Nov 28 09:08:39 AM CET 2025
lvm2-2.03.36-1.el10    BUILT: Sat Oct 25 04:42:32 AM CEST 2025
lvm2-libs-2.03.36-1.el10    BUILT: Sat Oct 25 04:42:32 AM CEST 2025
 
 
lvmpersist(8)
 
       local/pr_key
 
       The value set in pr_key will be used directly.  It is a hex string up to 16 characters long.  pr_key will not be used for sanlock shared VGs.
 
       local/host_id
 
       For a sanlock shared VG, or if no pr_key is set, a key will be created using the host_id.  This is a decimal integer between 1 and 2000.
# I don't really like the "or if no pr_key is set," above. That only applies to local VGs, and we're talking about shared in this paragraph. What it states is true, but is confusing in this paragraph, I had to read that a couple times. 
 
/etc/lvm/lvmlocal.conf
        # Configuration option local/host_id.
        # The sanlock host_id used by lvmlockd. This must be unique among all the hosts
        # using shared VGs with sanlock. Accepted values are 1-2000, except when sanlock_align_size
        # is configured to 1, 2 or 4, which correspond to max host_id values of 250, 500, or 1000.
        # When using persistent reservations, lvm will generate a PR key from the host_id
        # if pr_key is not defined. All hosts using a sanlock shared VG with PR must use

"When using persistent reservations, lvm will generate a PR key from the host_id if pr_key is not defined"  - That implication isn't true to my knowledge. Regardless of whether or not a pr_key is defined, LVM will ignore it wrt shared VGs

 
[root@virt-498 ~]# grep QA /etc/lvm/lvmlocal.conf 
        pr_key = "0xa63b3fe44bb87092"   # edited by QA Sun Dec 28 15:00:26 2025
        host_id = 1239   # edited by QA Sun Dec 28 15:00:34 2025
 
[root@virt-499 ~]#  grep QA /etc/lvm/lvmlocal.conf 
        pr_key = "0x46bf48dc8ddef1eb"   # edited by QA Sun Dec 28 15:00:28 2025
        host_id = 368   # edited by QA Sun Dec 28 15:00:35 2025
 
# These keys are hex versions of the host_id, so it didn't appear to matter that we had also set a pr_key.
[root@virt-498 ~]# vgchange --persist check persist_VG
  key for local host is registered: 0x10000000000104d7
  keys for all registered hosts: 0x100000000001009a 0x1000000000010170 0x10000000000104d7 
  reservation WEAR for registered hosts
  PR is started.
 
 
# If you remove the host_id, which none of the documents state you can, it'll fail
vgcreate --shared   persist_VG /dev/sda /dev/sdb /dev/sdc /dev/sdd /dev/sde
  Enabling sanlock global lock
  Invalid host_id 0, use 1-2000.
  Failed to initialize lock args for lock type sanlock
  Volume group "persist_VG" successfully removed