????公司使用了虛擬機環(huán)境，容量不夠的情況下，需要新加硬盤。但添加了新硬盤后，使用fdsik不能看到新硬盤。查找相關(guān)資料，有兩種思路可以選擇。

思路一

[root@node2 ~]# fdisk -l   #未識別新硬盤

Disk /dev/sda: 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
Disk label type: dos
Disk identifier: 0x0009f777

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     2099199     1048576   83  Linux
/dev/sda2         2099200    41943039    19921920   8e  Linux LVM

Disk /dev/mapper/centos-root: 18.2 GB, 18249416704 bytes, 35643392 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-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

查看/proc/scsi/scsi/ 下面

[root@node2 ~]# cat /proc/scsi/scsi 
Attached devices:#  這個直接存儲就是我們正在使用的總線
Host: scsi2 Channel: 00 Id: 00 Lun: 00
  Vendor: VMware,  Model: VMware Virtual S Rev: 1.0 
  Type:   Direct-Access                    ANSI  SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 00   # 注意類型，為光驅(qū)設(shè)備
  Vendor: NECVMWar Model: VMware IDE CDR10 Rev: 1.00
  Type:   CD-ROM                           ANSI  SCSI revision: 05

可使用命令直接進(jìn)行添加

echo “scsi add-single-device x y z u” >> /proc/scsi/scsi

注：對各個參數(shù)的理解：
x是硬盤所在SCSI控制器號（一般機器就一個SCSI控制器，所以就是0）；
y是硬盤所在SCSI通道的編號（一般單通道的就是0，多通道的要看是哪個通道了）
單通道SCSI卡最多支持同時接15個盤，卡上只一個通道。
雙通道SCSI卡有2個通道，在數(shù)量上增加一倍，可以同時并行各接15個，達(dá)到30個。
z是硬盤的SCSI ID號（在原有上面加1）；
u是硬盤的lun號（默認(rèn)情況都是0）

所以本次就可以直接使用

[root@node2 ~]# echo "scsi add-single-device 2 0 1 0 " >> /proc/scsi/scsi

[root@node2 ~]# fdisk  -l  # 已經(jīng)識別了sdb硬盤

Disk /dev/sda: 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
Disk label type: dos
Disk identifier: 0x0009f777

  Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     2099199     1048576   83  Linux
/dev/sda2         2099200    41943039    19921920   8e  Linux LVM

Disk /dev/mapper/centos-root: 18.2 GB, 18249416704 bytes, 35643392 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-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/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

思路二：觸發(fā)系統(tǒng)的磁盤掃描

[root@node2 ~]# cat /proc/scsi/scsi 
Attached devices:
Host: scsi2 Channel: 00 Id: 00 Lun: 00
  Vendor: VMware,  Model: VMware Virtual S Rev: 1.0 
  Type:   Direct-Access                    ANSI  SCSI revision: 02
Host: scsi1 Channel: 00 Id: 00 Lun: 00  
  Vendor: NECVMWar Model: VMware IDE CDR10 Rev: 1.00
  Type:   CD-ROM                           ANSI  SCSI revision: 05

[root@node2 ~]# ls /sys/class/scsi_host/
host0  host1  host2

此處可以使用暴力方法針對所有的總線進(jìn)行掃描

echo "- - -" > /sys/class/scsi_host/host0/scan
echo "- - -" > /sys/class/scsi_host/host1/scan
echo "- - -" > /sys/class/scsi_host/host2/scan
...

掃描后就會識別所有總線上的硬盤了