原因

检查后发现启动扇区未清零。

# 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

这表明磁盘上没有 pratition。
我们可以使用详细选项“-vvv”运行 pvcreate 命令以获取有关错误的更多详细信息：

# 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

调试输出中的最后一个条目表明原因在清零第一个扇区区域。

问题

使用pvcreate命令尝试创建物理卷时，出现以下错误：

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

解决方法

1. 对于整个磁盘设备，只需擦除分区表，这将有效地破坏该磁盘上的所有数据。
   这可以通过将第一个扇区归零来完成：

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

2. 执行 pvcreate 创建物理卷：

# pvcreate [device]

3. 根据需要将解决方案迁移到其他环境。