El problema
Al intentar crear un volumen físico, aparece el siguiente error
error:
# pvcreate /dev/mappper/mpath25 Device /dev/mappper/mpath25 not found (or ignored by filtering).
El problema se puede reproducir a voluntad con el siguiente paso:
# pvcreate /dev/mappper/mpath25
La solución
Al verificar, se encontró que el sector de inicio no se puso a cero.
# pvcreate /dev/mappper/mpath25 Device /dev/mappper/mpath25 not found (or ignored by filtering).
# fdisk -l /dev/mapper/mpath25 Disk /dev/mapper/mpath25 doesn't contain a valid partition table
Esto muestra que no había ninguna práctica presente en el disco. Puede ejecutar el comando pvcreate con la opción detallada "-vvv" para obtener más detalles sobre el error:
# pvcreate -vvv /dev/mapper/mpath25 Processing: pvcreate -vvv /dev/mapper/mpath25 O_DIRECT will be used Setting global/locking_type to 1 Setting global/wait_for_locks to 1 File-based locking selected. Setting global/locking_dir to /var/lock/lvm metadata/pvmetadataignore not found in config: defaulting to n metadata/pvmetadatasize not found in config: defaulting to 255 metadata/pvmetadatacopies not found in config: defaulting to 1 Locking /var/lock/lvm/P_orphans WB _do_flock /var/lock/lvm/P_orphans:aux WB _do_flock /var/lock/lvm/P_orphans WB _undo_flock /var/lock/lvm/P_orphans:aux dm version OF [16384] dm status (253:11) OF [16384] /dev/mapper/mpath25: New preferred name ### indicates that it can find the device Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: size is 629145600 sectors Closed /dev/mapper/mpath25 /dev/mapper/mpath25: size is 629145600 sectors Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: block size is 4096 bytes Closed /dev/mapper/mpath25 Using /dev/mapper/mpath25 Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: block size is 4096 bytes /dev/mapper/mpath25: No label detected Closed /dev/mapper/mpath25 dm status (253:11) OF [16384] Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: size is 629145600 sectors Closed /dev/mapper/mpath25 /dev/mapper/mpath25: size is 629145600 sectors Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: block size is 4096 bytes Closed /dev/mapper/mpath25 Using /dev/mapper/mpath25 Opened /dev/mapper/mpath25 RW O_EXCL O_DIRECT Closed /dev/mapper/mpath25 /dev/mapper/mpath25: size is 629145600 sectors Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: block size is 4096 bytes Closed /dev/mapper/mpath25 /dev/mapper/mpath25: size is 629145600 sectors Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: block size is 4096 bytes Closed /dev/mapper/mpath25 Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: block size is 4096 bytes Closed /dev/mapper/mpath25 dm status (253:11) OF [16384] Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: size is 629145600 sectors Closed /dev/mapper/mpath25 /dev/mapper/mpath25: size is 629145600 sectors Opened /dev/mapper/mpath25 RO O_DIRECT /dev/mapper/mpath25: block size is 4096 bytes Closed /dev/mapper/mpath25 Using /dev/mapper/mpath25 /dev/mapper/mpath25: size is 629145600 sectors Setting devices/data_alignment to 0 Setting devices/default_data_alignment to 0 /dev/mapper/mpath25: Setting PE alignment to 128 sectors. /dev/mapper/mpath25: Setting PE alignment offset to 0 sectors. Opened /dev/mapper/mpath25 RW O_DIRECT Wiping /dev/mapper/mpath25 at sector 8 length 8 sectors /dev/mapper/mpath25: block size is 4096 bytes Closed /dev/mapper/mpath25 Set up physical volume for "/dev/mapper/mpath25" with 629145600 available sectors Scanning for labels to wipe from /dev/mapper/mpath25 Opened /dev/mapper/mpath25 RW O_DIRECT /dev/mapper/mpath25: block size is 4096 bytes Closed /dev/mapper/mpath25 Zeroing start of device /dev/mapper/mpath25 Opened /dev/mapper/mpath25 RW O_DIRECT Wiping /dev/mapper/mpath25 at sector 0 length 4 sectors /dev/mapper/mpath25: block
Última entrada en la salida de depuración que indica que la causa está en el área del primer sector de puesta a cero.
Para implementar la solución, ejecute los siguientes pasos:
1. Para dispositivos de disco completo, solo se debe borrar la tabla de particiones, lo que destruirá efectivamente todos los datos en ese disco. Esto se puede hacer poniendo a cero el primer sector con:
# dd if=/dev/zero of=bs=512 count=1.
2. Ejecute pvcreate para crear el volumen físico:
# pvcreate [device]
3. Migre la solución según corresponda a otros entornos.