“AVVISO:impossibile connettersi a lvmetad. Ritorno alla scansione del dispositivo” – errore durante l'esecuzione dei comandi LVM

Il problema

I comandi LVM che mostrano di seguito gli errori:

# pvs
WARNING: Failed to connect to lvmetad. Falling back to device scanning.    <<<
PV VG Fmt Attr PSize PFree
/dev/sd[X][partition_number] [vg_name] lvm2 a-- [size]g [available_free_space]g

# vgs
WARNING: Failed to connect to lvmetad. Falling back to device scanning.    <<<
VG #PV #LV #SN Attr VSize VFree
[vg_name] [number_of_pvs]  [number of lvs] 0 wz--n- [size]g [available_free_space]g

# lvs
WARNING: Failed to connect to lvmetad. Falling back to device scanning.    <<<
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
[lv_name] [vg_name] -wi-ao---- [size]g

Errore dal file /var/log/messages:

# grep lvmetad /var/log/messages
Sep 8 20:34:29 [hostname] systemd: Cannot add dependency job for unit lvm2-lvmetad.socket, ignoring: Unit is masked.
Sep 8 20:34:29 [hostname] lvm: WARNING: Failed to connect to lvmetad. Falling back to device scanning.
Sep 8 20:34:31 [hostname] lvm: WARNING: Failed to connect to lvmetad. Falling back to device scanning.
Sep 8 20:34:31 [hostname]t lvm: pvscan[642] activating all directly (lvmetad unused) 8:17
Sep 8 20:34:31 [hostname] lvm: WARNING: Autoactivation reading from disk instead of lvmetad.
Sep 8 20:34:31 [hostname] lvm: WARNING: Failed to connect to lvmetad. Falling back to device scanning.
Sep 8 20:34:31 [hostname] lvm: pvscan[644] activating all directly (lvmetad unused) 8:2
Sep 8 20:34:31 [hostname] lvm: WARNING: Autoactivation reading from disk instead of lvmetad.

La soluzione

Il lvm2-lvmetad.service e lvm2-lvmetad.socket servizi sono stati disabilitati senza seguire i passaggi appropriati. Il /etc/lvm/lvm.conf è configurato per utilizzare use_lvmetad, mentre i servizi lvm2-lvmetad.service e lvm2-lvmetad.socket erano mascherati.

# grep "use_lvmetad =" /etc/lvm/lvm.conf
use_lvmetad = 1

# systemctl status lvm2-lvmetad.service
● lvm2-lvmetad.service
Loaded: masked (/dev/null; bad)      >>>>> Masked      
Active: inactive (dead)
Warning: lvm2-lvmetad.service changed on disk. Run 'systemctl daemon-reload' to reload units.

# systemctl status lvm2-lvmetad.socket
● lvm2-lvmetad.socket
Loaded: masked (/dev/null; bad)      >>>>> Masked
Active: inactive (dead)

Sep 08 20:34:29  systemd[1]: Cannot add dependency job for unit lvm2-lvmetad.socket, ignoring: Unit is masked.
Sep 08 20:34:32  systemd[1]: Cannot add dependency job for unit lvm2-lvmetad.socket, ignoring: Invalid request descriptor
Sep 08 20:34:38  systemd[1]: Cannot add dependency job for unit lvm2-lvmetad.socket, ignoring: Unit is masked.
Sep 08 20:34:38  systemd[1]: Cannot add dependency job for unit lvm2-lvmetad.socket, ignoring: Unit is masked.
Warning: lvm2-lvmetad.socket changed on disk. Run 'systemctl daemon-reload' to reload units.

- Smaschera lvm2-lvmetad.socket e lvm2-lvmetad.service primo. Quindi avvia e abilita i servizi all'avvio con i comandi seguenti.

# systemctl unmask lvm2-lvmetad.service lvm2-lvmetad.socket
# systemctl start lvm2-lvmetad.service lvm2-lvmetad.socket
# systemctl enable lvm2-lvmetad.service lvm2-lvmetad.socket

Se lvm2-lvmetad.socket e lvm2-lvmetad.service devono essere disabilitati, allora /etc/lvm/lvm.conf richiede di essere configurato per non usare "use_lvmetad". (cioè use_lvmetad =0)