CentOS新增硬盘，重新扫描总线

Centos 新增硬盘以后，系统不能自动进行识别。

1. 由于不知道新增硬盘挂载的位置，可以先查看现有硬盘挂载的适配器。

[root@localhost ~]# ls -l /sys/block/sda
lrwxrwxrwx. 1 root root 0 Jun 15 11:47 /sys/block/sda -> ../devices/pci0000:00/0000:00:10.0/host32/target32:0:0/32:0:0:0/block/sda

2. 发现正在磁盘挂载到host32，可以尝试使用下边命令，重新扫描host32信息

echo "- - -" > /sys/class/scsi_host/host32/scan 

3. 执行完成后，dmesg可以查看到新增硬盘信息。

[  620.865767] scsi 32:0:1:0: Direct-Access     VMware,  VMware Virtual S 1.0  PQ: 0 ANSI: 2
[  620.865800] scsi target32:0:1: Beginning Domain Validation
[  620.866413] scsi target32:0:1: Domain Validation skipping write tests
[  620.866416] scsi target32:0:1: Ending Domain Validation
[  620.866450] scsi target32:0:1: FAST-40 WIDE SCSI 80.0 MB/s ST (25 ns, offset 127)
[  620.870284] sd 32:0:1:0: Attached scsi generic sg2 type 0
[  620.870360] sd 32:0:1:0: [sdb] 2097152 512-byte logical blocks: (1.07 GB/1.00 GiB)
[  620.870408] sd 32:0:1:0: [sdb] Write Protect is off
[  620.870410] sd 32:0:1:0: [sdb] Mode Sense: 61 00 00 00
[  620.870734] sd 32:0:1:0: [sdb] Cache data unavailable
[  620.870736] sd 32:0:1:0: [sdb] Assuming drive cache: write through
[  620.874775] sd 32:0:1:0: [sdb] Cache data unavailable
[  620.874779] sd 32:0:1:0: [sdb] Assuming drive cache: write through
[  620.875859]  sdb: unknown partition table
[  620.876069] sd 32:0:1:0: [sdb] Cache data unavailable
[  620.876071] sd 32:0:1:0: [sdb] Assuming drive cache: write through
[  620.876123] sd 32:0:1:0: [sdb] Attached SCSI disk

4. fdisk -l 可以发现心中的/dev/sdb信息

Disk /dev/sdb: 1073 MB, 1073741824 bytes, 2097152 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

5. 现在就可以使用fdisk -l 或者parted命令进行分区操作了。

 从总线删除/dev/sdb硬盘（删除后，不能识别/dev/sdb硬盘了）

echo 1 > /sys/block/sdb/device/delete

另一种添加方法：

1. 增加硬盘后，查询不到新增加的硬盘信息

2.查看scsi信息

3. 增加scsi信息

 echo 'scsi add-single-device 0 0 1 0'>>/proc/scsi/scsi

代表scsc 0 ， channel 0 ，id 1，Lun 0  。将ID除，修改为1。

4. 增加后，能够查询到新增加硬盘