Debian10 LVM logical volumes

Basic terminology

come from Baidu Encyclopedia -LVM

• Physical storage medium （PhysicalStorageMedia）
  Refers to the physical storage device of the system ： disk , Such as ：/dev/hda、/dev/sda etc. , It's the bottom storage unit of the storage system .
• Physical volume （Physical Volume,PV）
  Refers to a disk partition or a device that logically has the same function as a disk partition （ Such as RAID）, yes LVM Block of basic storage logic , But with the basic physical storage medium （ Such as zoning 、 Disks, etc ） Compare , But contains and LVM Related management parameters .
• The volume group （Volume Group,VG）
  It's similar to not LVM Physical disks in the system , It consists of one or more physical volumes PV form . You can create one or more... On a volume group LV（ Logic volume ）.
• Logic volume （Logical Volume,LV）
  It's similar to not LVM Disk partition in the system , Logical volumes are built on volume groups VG above . In the logical volume LV You can build a file system （ such as /home perhaps /usr etc. ）.
• Physical block （Physical Extent,PE）
  PE Is a physical volume PV The basic division unit of , Having a unique number PE Yes, it can be. LVM The smallest unit of addressing .PE The size of is configurable , The default is 4MB. So physical volumes （PV） By basic units of equal size PE form .
• Logic block （Logical Extent,LE）
  Logic volume LV It is also divided into addressable basic units , be called LE. In the same volume group ,LE The size and PE It's the same , And one to one .
  

One 、 establish LVM Logical volumes and mount

#  install lvm2
apt install lvm2
#  see scsi Bus 
ls /sys/class/scsi_host
#  View results  host0 host1 host2
#  scanning host0
echo '- - -' > /sys/class/scsi_host/host0/scan
#  scanning host1
echo '- - -' > /sys/class/scsi_host/host1/scan
#  scanning host2
echo '- - -' > /sys/class/scsi_host/host2/scan
#  Check the disk   Find a new hard disk /dev/sdb
fdisk --list
#  Use cfdisk Initialize disk 
#  Use GPT Partition   establish Linux LVM Type of zoning 
cfdisk /dev/sdb
#  Check the disk   New partition found /dev/sdb1
fdisk --list
#  establish pv( Physical volume )
#  Parameters 1  Device path 
pvcreate /dev/sdb1
#  see pv list 
pvs
#  see pv details 
pvdisplay
#  establish vg( The volume group )
#  Parameters 1 -s PE size （ One vg most 65534 individual PE 256M Of vg The maximum capacity is 16T）
#  Parameters 2 vg name 
#  Parameters 3 pv name 
vgcreate -s 128M vg0 /dev/sdb1
#  see vg list 
vgs
#  see vg details 
vgdisplay
#  establish lv( Logic volume )
#  Parameters 1 -L  Logical volume size ( Actual capacity  10G 500G etc. )
#  Parameters 1 -l  Logical volume size (80%Free 100%VG etc. )
#  Parameters 2 -n  Logical volume name 
#  Parameters 3 vg0 For use vg Group 
lvcreate -l 100%Free -n vdisk0 vg0
#  see lv list 
lvs
#  see lv details 
lvdisplay
#  Check out the hard disk   Find out /dev/mapper/vg0-vdisk0 Logic volume 
fdisk --list
#  Format logical volume 
mkfs.ext4 /dev/vg0/vdisk0
#  Create mount point 
mkdir -p /opt/vdisk0
#  Mount logical volumes 
mount /dev/vg0/vdisk0 /opt/vdisk0
#  see UUID
blkid /dev/vg0/vdisk0
#  Check out the file system 
df -h
#  Power on auto mount 
#  Add a row UUID=xxxxxxxx /opt/vdisk0 ext4 defaults 0 0
# < file system > < Mount point > < Partition type > < Options > <dump Backup > < Check sector >
nano /etc/fstab

Two 、LVM command

command	purpose
pvchange	Change the properties of the physical volume
pvck	Check physical volume metadata
pvcreate	Initialize a disk or partition for LVM Use
pvdisplay	Show properties of physical volume
pvmove	Move physical volumes
pvremove	Delete physical volume
pvresize	adjustment LVM2 The size of the disk or partition used
pvs	View the list of physical volumes
pvscan	Scan all disks of the physical volume
vgcfgbackup	Backup volume group configuration
vgcfgrestore	Restore volume group configuration
vgchange	Change the properties of the volume group
vgck	Check volume group metadata
vgconvert	Transform volume group metadata format
vgcreate	Create a volume group
vgdisplay	Display the properties of the volume group
vgexport	Export volume groups
vgextend	Append physical volumes to volume groups
vgimport	Import volume group
vgimportclone	Import and rename duplicate volume groups （ For example, hardware snapshot ）
vgmerge	Merge two volume groups
vgmknodes	Recreate volume group directories and logical volume special files
vgreduce	Reduce volume groups by deleting one or more physical volumes
vgremove	Remove the volume group
vgrename	Rename volume group
vgs	Volume group list
vgscan	Scan all disks of the volume group
vgsplit	Split the volume group in two , Move any logical volume from one volume group to another by moving the entire physical volume
lvchange	Change the properties of the logical volume
lvconvert	Convert logical volumes from linear to mirror or snapshot
lvcreate	Create a logical volume in an existing volume group
lvdisplay	Show properties of logical volume
lvextend	Expand the size of the logical volume
lvreduce	Reduce the size of the logical volume
lvremove	Delete logical volume
lvrename	Rename logical volume
lvresize	Resize logical volume
lvs	List of logical volumes
lvscan	scanning （ All disks ） The logical volume
lvmconfig	Show lvm Configuration information
lvmdiskscan	Scan right LVM2 All visible devices
lvmdump	Create... For diagnostic purposes lvm2 memory dump

3、 ... and 、LVM Capacity expansion

#  see scsi Bus 
ls /sys/class/scsi_host
#  View results  host0 host1 host2
#  scanning host0
echo '- - -' > /sys/class/scsi_host/host0/scan
#  scanning host1
echo '- - -' > /sys/class/scsi_host/host1/scan
#  scanning host2
echo '- - -' > /sys/class/scsi_host/host2/scan
#  Check the disk   Find a new hard disk /dev/sdc
fdisk --list
#  Use cfdisk Initialize disk 
#  Use GPT Partition   establish Linux LVM Type of zoning 
cfdisk /dev/sdc
#  Check the disk   New partition found /dev/sdc1
fdisk --list
#  establish pv( Physical volume )
#  Parameters 1  Device path 
pvcreate /dev/sdc1
#  see VG
vgdisplay
#  Use vgextend hold pv Expand to vg0
#  Parameters 1 vg The volume group 
#  Parameters 2 pv Physical volume 
vgextend vg0 /dev/sdc1
#  see VG  Found free space ：Free PE/Size 239/<29.88 GiB
vgdisplay
# lv Capacity expansion  /dev/vg0/vdisk0
#  Parameters 1 -l  Adjust by percentage 
#  Parameters 2 lv Logic volume 
lvextend -l +100%FREE /dev/vg0/vdisk0
#  Resize partition   Expand all spaces by default 
resize2fs -p /dev/vg0/vdisk0
#  View the adjusted partition 
df -h

3、 ... and 、LVM Volume reduction

#  View partition mount 
df -h
#  Unload mount 
umount /opt/vdisk0
#  Check partition 
e2fsck -f /dev/vg0/vdisk0
#  Resize partition to 20G
resize2fs -p /dev/vg0/vdisk0 20G
#  Mount logical volumes 
mount /dev/vg0/vdisk0 /opt/vdisk0
# lv The logical volume capacity is adjusted to 20G（ Be careful ： Could damage data ）
lvreduce -L 20G /dev/vg0/vdisk0
#  View partition mount 
df -h
#  see vg Available space 
vgdisplay