如何不用重啟在CentOS 7/ RHEL 7虛擬機中添加一塊新硬盤

通常在你在虛擬機中添加一塊新硬盤時，你可能會看到新硬盤沒有自動加載。這是因為連接到硬盤的SCSI總線需要重新掃描來使得新硬盤可見。這裡有一個簡單的命令來重新掃描SCSI總線和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硬盤：

2. 顯示當前磁盤分區：

   1. [root@centos7 ~]# fdisk -l

   ---

   1. Disk/dev/sda:32.2 GB,32212254720 bytes,62914560 sectors
   2. Units= sectors of 1*512=512 bytes
   3. Sector size (logical/physical):512 bytes /512 bytes
   4. I/O size (minimum/optimal):512 bytes /512 bytes
   5. Disk label type: dos
   6. Disk identifier:0x0006b96a
   7. DeviceBootStartEndBlocksIdSystem
   8. /dev/sda1 *2048102604751200083Linux
   9. /dev/sda2 102604862914559309442568eLinux LVM
   10. Disk/dev/mapper/centos-swap:2147 MB,2147483648 bytes,4194304 sectors
   11. Units= sectors of 1*512=512 bytes
   12. Sector size (logical/physical):512 bytes /512 bytes
   13. I/O size (minimum/optimal):512 bytes /512 bytes
   14. Disk/dev/mapper/centos-root:29.5 GB,29536288768 bytes,57688064 sectors
   15. Units= sectors of 1*512=512 bytes
   16. Sector size (logical/physical):512 bytes /512 bytes
   17. I/O size (minimum/optimal):512 bytes /512 bytes

3. 確定主機總線號

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

4. 重新掃描SCSI總線來添加設備

   1. [root@centos7 ~]# echo "- - -">/sys/class/scsi_host/host0/scan
   2. [root@centos7 ~]# echo "- - -">/sys/class/scsi_host/host1/scan
   3. [root@centos7 ~]# echo "- - -">/sys/class/scsi_host/host2/scan

5. 驗證磁盤和分區並確保20GB硬盤已經添加了。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服務器就添加了新盤：

   1. [root@centos7 ~]# fdisk -l
   2. Disk/dev/sda:32.2 GB,32212254720 bytes,62914560 sectors
   3. Units= sectors of 1*512=512 bytes
   4. Sector size (logical/physical):512 bytes /512 bytes
   5. I/O size (minimum/optimal):512 bytes /512 bytes
   6. Disk label type: dos
   7. Disk identifier:0x0006b96a
   8. DeviceBootStartEndBlocksIdSystem
   9. /dev/sda1 *2048102604751200083Linux
   10. /dev/sda2 102604862914559309442568eLinux LVM
   11. Disk/dev/mapper/centos-swap:2147 MB,2147483648 bytes,4194304 sectors
   12. Units= sectors of 1*512=512 bytes
   13. Sector size (logical/physical):512 bytes /512 bytes
   14. I/O size (minimum/optimal):512 bytes /512 bytes
   15. Disk/dev/mapper/centos-root:29.5 GB,29536288768 bytes,57688064 sectors
   16. Units= sectors of 1*512=512 bytes
   17. Sector size (logical/physical):512 bytes /512 bytes
   18. I/O size (minimum/optimal):512 bytes /512 bytes
   19. Disk/dev/sdb:21.5 GB,21474836480 bytes,41943040 sectors
   20. Units= sectors of 1*512=512 bytes
   21. Sector size (logical/physical):512 bytes /512 bytes
   22. I/O size (minimum/optimal):512 bytes /512 bytes

更多CentOS相關信息見CentOS 專題頁面 http://www.linuxidc.com/topicnews.aspx?tid=14