“Perangkat /dev/mapper/mpath25 Tidak Ditemukan (atau Diabaikan Dengan Pemfilteran)” – kesalahan saat membuat volume fisik dengan pvcreate

Masalahnya

Saat mencoba membuat volume fisik, mendapatkan kesalahan di bawah ini

kesalahan:

# pvcreate /dev/mappper/mpath25
Device /dev/mappper/mpath25 not found (or ignored by filtering).

Masalah dapat direproduksi sesuka hati dengan langkah berikut:

# pvcreate /dev/mappper/mpath25

Solusinya

Setelah diperiksa, ternyata sektor awal tidak nol.

# 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

Ini menunjukkan bahwa tidak ada pratisi pada disk. Anda dapat menjalankan perintah pvcreate dengan opsi verbose “-vvv” untuk mendapatkan detail lebih lanjut tentang kesalahan:

# 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

Entri terakhir dalam output debug menunjukkan bahwa penyebabnya berada di area sektor pertama yang memusatkan perhatian.

Untuk mengimplementasikan solusi, lakukan langkah-langkah berikut:

1. Untuk seluruh perangkat disk hanya tabel partisi yang harus dihapus, yang secara efektif akan menghancurkan semua data pada disk tersebut. Ini dapat dilakukan dengan memusatkan sektor pertama dengan:

# dd if=/dev/zero of= bs=512 count=1.

2. Lakukan pvcreate untuk membuat volume fisik:

# pvcreate [device]

3. Migrasikan solusi yang sesuai ke lingkungan lain.