如何不用重啟在CentOS 7/ RHEL 7虛擬機中添加一塊新硬碟

通常在你在虛擬機中添加一塊新硬碟時，你可能會看到新硬碟沒有自動載入。這是因為連接到硬碟的SCSI匯流排需要重新掃描來使得新硬碟可見。這裡有一個簡單的命令來重新掃描SCSI匯流排和SCSI設備。下面這幾步在CentOS 7 和RHEL 7 中測試過。

1. 在ESXi或者vCenter中添加一塊新的20G硬碟：

2. 顯示當前磁碟分區：

[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

3. 確定主機匯流排號

[root@centos7 ~]# ls /sys/class/scsi_host/
host0  host1  host2

4. 重新掃描SCSI匯流排來添加設備

[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

5. 驗證磁碟和分區並確保20GB硬碟已經添加了。在本例中，出現了下面這行 「Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors」 並且可以確認沒有重啟伺服器就添加了新盤：

[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

via: http://www.ehowstuff.com/how-to-add-a-new-hard-disk-without-rebooting-on-centos-7-rhel-7/

作者：skytech 譯者：geekpi 校對：wxy

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