Vmware擴展磁盤如何不需重啓系統

    在虛擬機Vmware中咱們有時候須要添加新的虛擬磁盤或給已有虛擬磁盤擴容（expand），在新增磁盤或磁盤擴容後，Linux系統並不能立刻識別到。也就是說你看不到磁盤空間變化（使用fdisk -l查看），這時咱們能夠經過重啓系統（reboot）解決這個問題，可是不少時候，咱們並不想在存儲擴容時重啓系統，由於這樣會影響到現有的業務系統。那麼爲何新增磁盤或磁盤擴容後，Linux系統識別不到呢？這個是由於鏈接存儲設備的SCSI總線須要從新掃描，才能識別到這些新的存儲設備。下面測試一下在添加新的虛擬磁盤或給已有虛擬磁盤擴容如何操做才能不用重啓系統

1：Vmware虛擬磁盤擴容

以下所示，Vmware虛擬磁盤擴容後，使用fdisk -l看不到任何變化

[root@localhost ~]# fdisk -l

Disk /dev/sda: 171.7 GB, 171798691840 bytes

255 heads, 63 sectors/track, 20886 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          13      104391   83  Linux

/dev/sda2              14       15665   125724690   8e  Linux LVM

/dev/sda3           15666       15795     1044225   83  Linux

/dev/sda4           15796       20886    40893457+  83  Linux

Disk /dev/dm-0: 126.6 GB, 126600871936 bytes

255 heads, 63 sectors/track, 15391 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/dm-0 doesn't contain a valid partition table

Disk /dev/dm-1: 2113 MB, 2113929216 bytes

255 heads, 63 sectors/track, 257 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/dm-1 doesn't contain a valid partition table

 

 

方法1：echo 1 > /sys/class/scsi_device/device/rescan

[root@localhost ~]# cd /sys/class/scsi_disk/

[root@localhost scsi_disk]# ls

0:0:0:0

[root@localhost scsi_disk]# cd 0\:0\:0\:0/

[root@localhost 0:0:0:0]# echo '1' > device/rescan 

[root@localhost 0:0:0:0]# fdisk -l

Disk /dev/sda: 173.9 GB, 173946175488 bytes

255 heads, 63 sectors/track, 21147 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System

/dev/sda1   *           1          13      104391   83  Linux

/dev/sda2              14       15665   125724690   8e  Linux LVM

/dev/sda3           15666       15795     1044225   83  Linux

/dev/sda4           15796       20886    40893457+  83  Linux

Disk /dev/dm-0: 126.6 GB, 126600871936 bytes

255 heads, 63 sectors/track, 15391 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/dm-0 doesn't contain a valid partition table

Disk /dev/dm-1: 2113 MB, 2113929216 bytes

255 heads, 63 sectors/track, 257 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/dm-1 doesn't contain a valid partition table

 

方法2：從新掃描特定的 SCSI Device

echo 1 > /sys/block/$DEVICE/device/rescan 用sda, sdb, sdc等替換$DEVICE

[root@localhost ~]# echo 1 > /sys/block/sda/device/rescan

2：Vmware新增虛擬磁盤

首先找到您的主機總線編號

[root@localhost ~]# grep mpt /sys/class/scsi_host/host?/proc_name

/sys/class/scsi_host/host0/proc_name:mptspi

使用下面命令掃描SCSI總線

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

參考資料：

http://thornelabs.net/2012/08/22/linux-rescan-scsi-bus.html