测试环境硬盘不够用了，做了lvm新插了块硬盘扩容，结果在系统里 fdisk -l 却看不到新加的硬盘，又不想重启怎么办？
[root@owner-node1:~]# fdisk -l
Disk /dev/sda: 536.9 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000387ab
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 1046 8192000 82 Linux swap / Solaris
/dev/sda3 1046 65271 515890176 83 Linux
一条命令就可以搞定：
# 注意“- - -”中间有空格
[root@owner-node1:~]# echo "- - -" > /sys/class/scsi_host/host0/scan
[root@owner-node1:~]# echo "- - -" > /sys/class/scsi_host/host1/scan
[root@owner-node1:~]# echo "- - -" > /sys/class/scsi_host/host2/scan
[root@owner-node1:~]# echo "- - -" > /sys/class/scsi_host/host3/scan
[root@owner-node1:~]# echo "- - -" > /sys/class/scsi_host/host4/scan
[root@owner-node1:~]# echo "- - -" > /sys/class/scsi_host/host5/scan
[root@owner-node1:~]# echo "- - -" > /sys/class/scsi_host/host6/scan
再用 fdisk -l 就看到了
[root@owner-node1:~]# fdisk -l
Disk /dev/sda: 536.9 GB, 536870912000 bytes
255 heads, 63 sectors/track, 65270 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000387ab
Device Boot Start End Blocks Id System
/dev/sda1 * 1 26 204800 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2 26 1046 8192000 82 Linux swap / Solaris
/dev/sda3 1046 65271 515890176 83 Linux
Disk /dev/sdb: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
其中是host0还是host1…，跟新插入的硬盘口有关系，不清楚就逐个试一遍好了
