No such logical volume pve/data (500) after multipath -a: fix Proxmox local-lvm

Running multipath -a on a Proxmox host can break local-lvm with the error no such logical volume pve/data (500). The thin pool pve/data disappears from LVM because multipath grabs the underlying disk and renames it. Fix is to remove the multipath mapping and rescan LVM.

Why multipath breaks pve/data

Proxmox installs local-lvm as an LVM thin pool on top of a physical disk, usually /dev/sda or /dev/nvme0n1. When you run multipath -a, the multipath daemon claims that disk and creates a new device like /dev/mapper/mpatha. LVM still has the physical volume registered on the old device name, but that device is no longer accessible. Result: lvs shows the volume group but can’t find the logical volume, and Proxmox throws the 500 error.

Check what happened

First confirm the disk got claimed by multipath:

multipath -ll
lsblk

You’ll see mpatha or similar on the disk that used to hold pve. The LVM tools still look for /dev/sda but that’s gone.

Fix: remove the multipath mapping

If you don’t actually need multipath (most homelabs don’t), just remove the mapping and rescan LVM:

multipath -f /dev/mapper/mpatha
vgscan --mknodes
lvchange -ay pve/data

Replace mpatha with whatever multipath -ll showed. After that, lvs should show pve/data again and Proxmox will stop complaining.

If you do need multipath

For actual multipath setups, you need to exclude the Proxmox disk from multipath. Edit /etc/multipath.conf and add a blacklist entry for the disk’s WWID or device name:

blacklist {
    wwid 3600508b1001c...
}

Then restart multipathd and rescan LVM. But honestly, if you’re running a single disk homelab, just don’t enable multipath on the Proxmox disk. It’s a pain in the butt for no benefit.

Related: if you’re messing with local-lvm anyway, check Need to delete local-lvm and reuse the size in Proxmox.