CentOS在不重启的情况下为其虚拟机添加新硬盘的教程

 　　通常在你在虚拟机中添加一块新硬盘时，你可能会看到新硬盘没有自动加载。这是因为连接到硬盘的SCSI总线需要重新扫描来使得新硬盘可见。这里有一个简单的命令来重新扫描SCSI总线和SCSI设备。下面这几步在CentOS 7 和RHEL 7 中测试过。

　　在ESXi或者vCenter中添加一块新的20G硬盘：

　　显示当前磁盘分区：

　　代码如下:

　　[root@centos7 ~]# fdisk -l

Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors

　　Units = sectors of 1 * 512 = 512 bytes

　　Sector size (logical/physical): 512 bytes / 512 bytes

　　I/O size (minimum/optimal): 512 bytes / 512 bytes

　　Disk label type: dos

　　Disk identifier: 0x0006b96a

　　Device Boot Start End Blocks Id System

　　/dev/sda1 * 2048 1026047 512000 83 Linux

　　/dev/sda2 1026048 62914559 30944256 8e Linux LVM

　　Disk /dev/mapper/centos-swap: 2147 MB, 2147483648 bytes, 4194304 sectors

　　Units = sectors of 1 * 512 = 512 bytes

　　Sector size (logical/physical): 512 bytes / 512 bytes

　　I/O size (minimum/optimal): 512 bytes / 512 bytes

　　Disk /dev/mapper/centos-root: 29.5 GB, 29536288768 bytes, 57688064 sectors

　　Units = sectors of 1 * 512 = 512 bytes

　　Sector size (logical/physical): 512 bytes / 512 bytes

　　I/O size (minimum/optimal): 512 bytes / 512 bytes

　　确定主机总线号

　　代码如下:

　　[root@centos7 ~]# ls /sys/class/scsi_host/

　　host0 host1 host2

　　重新扫描SCSI总线来添加设备

　　代码如下:

　　[root@centos7 ~]# echo "- - -" > /sys/class/scsi_host/host0/scan

　　[root@centos7 ~]# echo "- - -" > /sys/class/scsi_host/host1/scan

　　[root@centos7 ~]# echo "- - -" > /sys/class/scsi_host/host2/scan

　　验证磁盘和分区并确保20GB硬盘已经添加了。在本例中，出现了下面这行 “Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors” 并且可以确认没有重启服务器就添加了新盘：

　　代码如下:

　　[root@centos7 ~]# fdisk -l

　　Disk /dev/sda: 32.2 GB, 32212254720 bytes, 62914560 sectors

　　Units = sectors of 1 * 512 = 512 bytes

　　Sector size (logical/physical): 512 bytes / 512 bytes

　　I/O size (minimum/optimal): 512 bytes / 512 bytes

　　Disk label type: dos

　　Disk identifier: 0x0006b96a

　　Device Boot Start End Blocks Id System

　　/dev/sda1 * 2048 1026047 512000 83 Linux

　　/dev/sda2 1026048 62914559 30944256 8e Linux LVM

　　Disk /dev/mapper/centos-swap: 2147 MB, 2147483648 bytes, 4194304 sectors

　　Units = sectors of 1 * 512 = 512 bytes

　　Sector size (logical/physical): 512 bytes / 512 bytes

　　I/O size (minimum/optimal): 512 bytes / 512 bytes

　　Disk /dev/mapper/centos-root: 29.5 GB, 29536288768 bytes, 57688064 sectors

　　Units = sectors of 1 * 512 = 512 bytes

　　Sector size (logical/physical): 512 bytes / 512 bytes

　　I/O size (minimum/optimal): 512 bytes / 512 bytes

　　Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors

　　Units = sectors of 1 * 512 = 512 bytes

　　Sector size (logical/physical): 512 bytes / 512 bytes

　　I/O size (minimum/optimal): 512 bytes / 512 bytes