为什么执行“fdisk -l”的时候，软RAID设备出现“Disk /dev/mdN doesn't contain a valid partition table”这样的警告?

Issue

为什么执行“fdisk -l”的时候，软RAID设备出现“Disk /dev/mdN doesn't contain a valid partition table”这样的警告?

    [root@HOSTNAME ~]# fdisk -l

    Disk /dev/sda: 160.0 GB, 160041885696 bytes
    255 heads, 63 sectors/track, 19457 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes

       Device Boot      Start         End      Blocks   Id  System
    /dev/sda1   *           1          13      104391   fd  Linux raid autodetect
    /dev/sda2              14       19457   156183930   fd  Linux raid autodetect

    Disk /dev/sdb: 160.0 GB, 160041885696 bytes
    255 heads, 63 sectors/track, 19457 cylinders
    Units = cylinders of 16065 * 512 = 8225280 bytes

       Device Boot      Start         End      Blocks   Id  System
    /dev/sdb1   *           1          13      104391   fd  Linux raid autodetect
    /dev/sdb2              14       19457   156183930   fd  Linux raid autodetect

    Disk /dev/md1: 159.9 GB, 159932219392 bytes
    2 heads, 4 sectors/track, 39045952 cylinders
    Units = cylinders of 8 * 512 = 4096 bytes

    Disk /dev/md1 doesn't contain a valid partition table

    Disk /dev/md0: 106 MB, 106823680 bytes
    2 heads, 4 sectors/track, 26080 cylinders
    Units = cylinders of 8 * 512 = 4096 bytes

    Disk /dev/md0 doesn't contain a valid partition table