Linux LVM学习总结——扩展卷组VG

Linux服务器由于应用变更或需求的缘故，有可能出现分区空间不足的情况，此时往往需要进行扩容（要增加分区的空间），而采用LVM的好处就是可以在不需停机的情况下可以方便地调整各个分区大小。如下所示，分区/u05由于备份集保留的时间调整，RMAN备份时出现空间不足的情况，如下所示，

[root@getlnx01 ~]# df -h

Filesystem Size Used Avail Use% Mounted on

/dev/mapper/VolGroup00-LogVol00

 97G 37G 55G 41% /

/dev/mapper/VolGroup01-LogVol00

 79G 33G 43G 44% /u01

/dev/mapper/VolGroup02-LogVol00

 197G 168G 19G 90% /u02

/dev/mapper/VolGroup03-LogVol00

 197G 127G 60G 68% /u03

/dev/mapper/VolGroup04-LogVol00

 138G 126G 5.6G 96% /u04

/dev/mapper/VolGroup05-LogVol00

 178G 104G 65G 62% /u05

/dev/sda1 99M 23M 71M 25% /boot

tmpfs 12G 0 12G 0% /dev/shm

[root@getlnx01 ~]# vgscan

 Reading all physical volumes. This may take a while...

 Found volume group "VolGroup05" using metadata type lvm2

 Found volume group "VolGroup04" using metadata type lvm2

 Found volume group "VolGroup03" using metadata type lvm2

 Found volume group "VolGroup02" using metadata type lvm2

 Found volume group "VolGroup01" using metadata type lvm2

 Found volume group "VolGroup00" using metadata type lvm2

[root@getlnx01 ~]# 

我在添加了一块虚拟磁盘后（虚拟机），此时使用fdisk -l查不到刚刚添加的新磁盘，此时需要运行命令echo "- - -" > /sys/class/scsi_host/host0/scan重新扫描该接口下的SCSI磁盘设备。

关于该命令它是通过/sys下的属性设置运行SCSI扫描。echo "- - -" > scan "- - -"代表channel，target和LUN编号。以上命令会导致hba4下所有channel，target以及可见LUN被扫描。

[root@getlnx01 ~]# echo "- - -" > /sys/class/scsi_host/host0/scan

[root@getlnx01 ~]# fdisk -l

Disk /dev/sda: 55.8 GB, 55834574848 bytes

255 heads, 63 sectors/track, 6788 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 6788 54420187+ 8e Linux LVM

Disk /dev/sdb: 85.8 GB, 85899345920 bytes

255 heads, 63 sectors/track, 10443 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

 Device Boot Start End Blocks Id System

/dev/sdb1 1 10443 83883366 5 Extended

/dev/sdb5 1 10443 83883334+ 83 Linux

Disk /dev/sdd: 214.7 GB, 214748364800 bytes

255 heads, 63 sectors/track, 26108 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

 Device Boot Start End Blocks Id System

/dev/sdd1 1 26108 209712478+ 5 Extended

/dev/sdd5 1 26108 209712447 83 Linux

Disk /dev/sdc: 214.7 GB, 214748364800 bytes

255 heads, 63 sectors/track, 26108 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

 Device Boot Start End Blocks Id System

/dev/sdc1 1 26108 209712478+ 5 Extended

/dev/sdc5 1 26108 209712447 83 Linux

Disk /dev/sdf: 64.4 GB, 64424509440 bytes

255 heads, 63 sectors/track, 7832 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

 Device Boot Start End Blocks Id System

/dev/sdf1 1 7832 62910508+ 5 Extended

/dev/sdf5 1 7832 62910477 83 Linux

Disk /dev/sde: 150.3 GB, 150323855360 bytes

255 heads, 63 sectors/track, 18275 cylinders

Units = cylinders of 16065 * 512 = 8225280 bytes

 Device Boot Start End Blocks Id System