Experiment: creation, expansion, and deletion of LVM logical volumes

Catalog

One 、LVM Establishment of logical volumes

Two 、LVM Logical volume expansion  

3、 ... and 、 Volume group expansion

Four 、LVM Logical volume deletion

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LVM The role of logical volumes ： Dynamically adjust the capacity of the disk , flexible , Can shrink elastically

One 、LVM Establishment of logical volumes

Ideas ： Add and identify hard disk ---》[ optional ] Disk partition ----》 Define physical disks pv -----》 Define volume groups vg  -----》 Define logical volumes lvm ------》 format   -------》 Mount the use

step ：

One 、 Add and identify hard disk

Add 4 A disk , Every disk 20G.

  Let the system be distinguish Hard disk has two ways ：① Restart the virtual machine

           ② Refresh the console ：echo "- - -" > /sys/class/scsi_host/host0/scan

                                               echo "- - -" > /sys/class/scsi_host/host1/scan

                                               echo "- - -" > /sys/class/scsi_host/host2/scan

Two 、

1、 Experimental environment preparation , Turn off firewall , Turn off core protection

2、 take sdb Defined as a 20G The partition , Change the type to 8e,LVM type

 3、 take sdc Defined as a 20G The partition , Change the type to 8e,LVM type

 4、 Create a physical volume   Define object as sdb1 and sdc1

Grammar format :pvcreate /dev/sdb1 /dev/sdc1 

see pvdisplay

5、 Create a volume group . The object is defined as a physical volume sdb1 and sdc1.

Grammar format ：vgcreate      Volume group name     Physical volume name   [ Physical volume name ]       

                  vgcreate vgname /dev/sdb1 /dev/sdc1

see vgdisplay  

 6、 Create logical volumes LVM.  

Grammar format ：lvcreate  -L Capacity size -n Logical volume name   Volume group name

                  lvcreate -L 10G -n ljj vgname 

see lvdisplay

 6、 format .

Grammar format ： mkfs.xfs+ Format object location

                 mkfs.xfs /dev/vgname/ljj  perhaps  mkfs -t xfs /dev/vgname/ljj

 7、 stay / So let's make a new one data2 Directory as mount point

8、① Mount the logical volume .（ To mount temporarily ）

② Permanently mount   vim /etc/fstab

  9、 Display all disk information .

Two 、LVM Logical volume expansion  

Is a logical volume ljj Disk space increases 10G

1、 Logical volume expansion

Grammar format ：lvextend -L +10G /dev/vgname/ljj

2、 You need to format the expanded disk space before you can mount it for use .（ Logical volume expansion , Only when it is mounted can the new part of the formatted speech be added , If it is not mounted, it cannot be formatted , Will report a mistake ）

Grammar format ：xfs_growfs /dev/vgname/ljj        Refresh xfs File system capacity , It is equivalent to expanding 10G format

 3、 Query disk information

ps( Minor fault analysis ): Problems arise : After the logical volume is expanded, the newly added part cannot be formatted .

① View mount status ：lvname The logical volume is mounted

② Format some new logical volumes and report errors

 ③ Mount logical volumes

④ Then carry on the format words , success  

3、 ... and 、 Volume group expansion

1、 First add a partition .

2、 Volume group expansion （sdd1 If it is not defined as a physical volume, it can also be added to the volume group , After joining the volume group, it will display sdd1 Is the physical volume type ）（ Complete in the case of mounting ）

Grammar format ： vgextend + Select the volume group name to be expanded + Expanded partition

vgextend vgname /dev/sdd1

Display volume group information    vgdisplsy 

Four 、LVM Logical volume deletion

Delete lvm Logical volume thinking ： Unmount -----》 Delete LV Logic volume ------》 Delete VG The volume group   -----》 Delete PV Physical volume ---》[ Change partition type ]

1、 Unmount   umount 

 2、 Delete logical volume   ljj

lvremove 

 3、 Remove the volume group

4、 Delete physical volume

summary ：

Attention in the experiment ：

Logical volume creation steps ： Add and identify hard disk ---》[ optional ] Disk partition ----》 Define physical disks pv -----》 Define volume groups vg  -----》 Define logical volumes lvm ------》 format   -------》 Mount the use

Logical volume deletion ideas ： Unmount -----》 Delete LV Logic volume ------》 Delete VG The volume group   -----》 Delete PV Physical volume ---》[ Change partition type ]

1、 After the logical volume is expanded, it needs to be formatted before it can be mounted for use

2、 Volume group expansion The newly added partition does not need to be defined as a physical volume , Can be used directly , It is also unnecessary to change to 8e   LVM.