虚拟机硬盘空间不够了，做了lvm准备加块硬盘扩容，在vcenter控制台加了磁盘，结果操作系统里面fdisk -l看不到新加的硬盘，又不想重启怎么办，一条命令就可以搞定。
# 注意中间有空格
echo "- - -" > /sys/class/scsi_host/host0/scan
[root@web03_back:/data]# 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
[root@web03_back:/data]# echo "- - -" > /sys/class/scsi_host/host
host0/ host1/ host2/
[root@web03_back:/data]# echo "- - -" > /sys/class/scsi_host/host0/scan
[root@web03_back:/data]# echo "- - -" > /sys/class/scsi_host/host1/scan
[root@web03_back:/data]# echo "- - -" > /sys/class/scsi_host/host2/scan
[root@web03_back:/data]# 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
再用fdisk -l就看到了
当然是host0还是host1，…，具体应该跟加硬盘时选择的挂载点有关系，不清楚就逐个试一遍好了