Article Directory
- 1. LVM logical volume management
- Second, create an LVM logical volume
- 1. Physical volume management (pv)
- 1.1 Create a physical volume --pvcreate
- 1.2 View physical volume—pvscan & pvdisplay
- 1.3 Delete the physical volume-pvremove
- 2. Volume group management (vg)
- 2.1 Create Volume Group-vgcreate
- 2.2 View volume group—vgscan & vgdisplay
- 2.3 increase the volume group capacity-vgextend
- 2.4 reduce volume group capacity-vgreduce
- 2.5 delete volume group-vgremove
- 3. Logical volume management (lv)
1. LVM logical volume management
1. Concept
LVM (Logical Volume Manager) is a mechanism for managing disks and partitions in the Linux environment.
Ordinary disk partition management methods cannot generally change their size after the partition is divided (risk)
LVM is to merge the object pv into one or several large vgs, and divide the vg space according to our needs. Since it is a virtual storage pool, you can freely adjust the size when dividing the space
The focus of LVM is that the capacity of the file system can be adjusted flexibly, not the efficiency and safety of data storage **
2. Components of LVM
Physical volume (PV, Physical Volume): converted from disk or partition
Volume group (VG, Volume Group): Multiple physical volumes are combined together to form a volume group. The same volume group can be composed of different partitions of the same hard disk or different partitions on different hard disks. We usually put Volume group is understood as a hard disk.
Logical Volume (LV, Logical Volume): If the volume group is understood as a hard disk, then our logical volume is a partition on the hard disk, and the logical volume can be formatted to store data.
Physical extension (PE, Physical Extend): The smallest storage unit of PE volume group. The location of PE is VG volume group, that is, on the hard disk, then we can understand PE as a sector on the hard disk, the default is 4MB, can be freely configured .
Second, create an LVM logical volume
(1) Partition the disk, or the entire disk is not partitioned
(2) Establish the partition or the entire disk on the disk into a physical volume (PV)
(3) Combine the created physical volumes into a volume group (VG), pass Add or delete a physical volume to adjust the volume group size.
(4) Finally, the volume group is divided into logical volumes (LV). The logical volume can also be adjusted at will. The logical volume is equivalent to a real partition, so it must be formatted and mounted.
Use fdisk to partition, the system ID of the partition needs to be modified to 8e00 using the t option
1. Physical volume management (pv)
1.1 Create Physical Volume-pvcreate
Format: pvcreate disk name / partition name
Partition:
entire hard drive:
1.2 View physical volume—pvscan & pvdisplay
Format:
pvs is short for
pvscan
pvdisplay pvdisplay specifies the disk name / partition name
[root@xxx ~]# :pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <19.00g 0
/dev/sdd1 lvm2 --- 10.00g 10.00g
/dev/sde lvm2 --- 20.00g 20.00g
[root@xxx ~]# :pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name centos
PV Size <19.00 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 4863
Free PE 0
Allocated PE 4863
PV UUID CQu05U-dzdQ-QkTT-W4OR-EaIW-f7EV-cC9sJi
"/dev/sdd1" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdd1
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID wvT7tu-mSmu-OzjE-oNrQ-4ILN-S38J-hscKsx
"/dev/sde" is a new physical volume of "20.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sde
VG Name
PV Size 20.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID fF8Umg-JrkA-NAMu-QTMI-ebds-NFTD-HS1osw
1.3 Delete the physical volume-pvremove
Format:
pvremove disk name / partition name
[root@xxx ~]# :pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <19.00g 0
/dev/sdd1 lvm2 --- 10.00g 10.00g
/dev/sde lvm2 --- 20.00g 20.00g
/dev/sdf lvm2 --- 20.00g 20.00g
[root@xxx ~]# :pvremove /dev/sdf
Labels on physical volume "/dev/sdf" successfully wiped.
You have new mail in /var/spool/mail/root
[root@xxx ~]# :pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <19.00g 0
/dev/sdd1 lvm2 --- 10.00g 10.00g
/dev/sde lvm2 --- 20.00g 20.00g
2. Volume group management (vg)
2.1 Create Volume Group-vgcreate
Format:
vgcreate option volume group name disk name / partition name (you can write multiple, separated by spaces)
-s size: specify the PE size of VG
[root@xxx ~]# :vgcreate -s 2M vg1 /dev/sdd1 /dev/sde
Volume group "vg1" successfully created
2.2 View volume group—vgscan & vgdisplay
Format:
vgs is short for vgscan
vgdisplay
vgdisplay specifies the disk name / partition name
[root@xxx ~]# :vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- <19.00g 0
vg1 2 0 0 wz--n- <30.00g <30.00g
[root@xxx ~]# :vgdisplay
--- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size <19.00 GiB
PE Size 4.00 MiB
Total PE 4863
Alloc PE / Size 4863 / <19.00 GiB
Free PE / Size 0 / 0
VG UUID d4wUf7-yU7O-0hdk-ohdD-4UME-TIBw-qQMQyr
--- Volume group ---
VG Name vg1
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size <30.00 GiB
PE Size 2.00 MiB
Total PE 15358
Alloc PE / Size 0 / 0
Free PE / Size 15358 / <30.00 GiB
VG UUID 1U8tJu-cHBt-B8TV-Ao2j-t29G-ULc3-DlHB04
2.3 increase volume group capacity-vgextend
Format:
vgextend volume group name disk name / partition name
[root@xxx ~]# :vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- <19.00g 0
vg1 1 0 0 wz--n- <10.00g <10.00g
[root@xxx ~]# :vgextend vg1 /dev/sde
Volume group "vg1" successfully extended
You have new mail in /var/spool/mail/root
[root@xxx ~]# :vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- <19.00g 0
vg1 2 0 0 wz--n- <30.00g <30.00g
2.4 Reduce volume group capacity-vgreduce
Be careful when deleting
Format:
vgreduce volume group name physical volume name
[root@xxx ~]# :vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- <19.00g 0
vg1 2 0 0 wz--n- <30.00g <30.00g
[root@xxx ~]# :vgreduce vg1 /dev/sde
Removed "/dev/sde" from volume group "vg1"
You have new mail in /var/spool/mail/root
[root@xxx ~]# :vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- <19.00g 0
vg1 1 0 0 wz--n- <10.00g <10.00g
2.5 delete volume group-vgremove
Format:
vgremove volume group name
Seeing the VG column, the volume group is deleted
[root@xxx ~]# :pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <19.00g 0
/dev/sdd1 vg1 lvm2 --- 10.00g 10.00g
/dev/sde vg1 lvm2 --- 20.00g 20.00g
[root@xxx ~]# :vgremove vg1
Volume group "vg1" successfully removed
[root@xxx ~]# :pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- <19.00g 0
/dev/sdd1 lvm2 --- 10.00g 10.00g
/dev/sde lvm2 --- 20.00g 20.00g
3. Logical volume management (lv)
3.1 Create Logical Volume --lvcreate
Format:
lvcreate parameter -n logical volume name volume group name
Parameters:
-L capacity: specify the size of the created logical volume, unit: MB, GB, TB, etc.
-l (small) number: specify the size of the
logical volume according to the number of PE -n logical volume name: specify the name of the logical volume
[root@xxx ~]# :lvcreate -L 15G -n lv1 vg1
Logical volume "lv1" created.
Note: Because the logical volume is equivalent to a partition, it needs to be formatted and mounted before it can be used, and self-starting
[root@xxx ~]# :mkfs.xfs /dev/vg1/lv1
meta-data=/dev/vg1/lv1 isize=512 agcount=4, agsize=983040 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=3932160, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
You have new mail in /var/spool/mail/root
[root@xxx ~]# :mkdir /disk/guazai5
[root@xxx ~]# :mount /dev/vg1/lv1 /disk/guazai5
[root@xxx ~]# :df -h | grep movie
You have new mail in /var/spool/mail/root
[root@xxx ~]# :df -h | grep /disk/guazai5
/dev/mapper/vg1-lv1 15G 33M 15G 1% /disk/guazai5
[root@xxx ~]# :echo "/dev/vg1/lv1 /disk/guazai5 xfs defaults 0 0" >> /etc/fstab
[root@xxx ~]# :mount -a
[root@xxx ~]# :df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 17G 2.7G 15G 16% /
devtmpfs 475M 0 475M 0% /dev
tmpfs 487M 0 487M 0% /dev/shm
tmpfs 487M 7.7M 479M 2% /run
tmpfs 487M 0 487M 0% /sys/fs/cgroup
/dev/sdc1 20G 483M 20G 3% /disk/guazai4
/dev/sdb1 10G 33M 10G 1% /disk/guazai3
/dev/sda1 1014M 133M 882M 14% /boot
tmpfs 98M 0 98M 0% /run/user/0
/dev/mapper/vg1-lv1 15G 33M 15G 1% /disk/guazai5
3.2 View Logical Volume—lvscan & lvdisplay
Format:
lvs is short for lvscan
lvdisplay
[root@xxx ~]# :lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
root centos -wi-ao---- <17.00g
swap centos -wi-ao---- 2.00g
lv1 vg1 -wi-ao---- 15.00g
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[root@xxx ~]# :lvdisplay
--- Logical volume ---
LV Path /dev/vg1/lv1
LV Name lv1
VG Name vg1
LV UUID Oxd3vD-Q0wD-QHb0-bf6o-3TEJ-VV08-DI01U9
LV Write Access read/write
LV Creation host, time xxx, 2020-04-22 23:42:51 -0400
LV Status available
# open 1
LV Size 15.00 GiB
Current LE 7680
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
--- Logical volume ---
LV Path /dev/centos/swap
LV Name swap
VG Name centos
LV UUID AmBZcm-EgKm-4Lx7-WSUf-KYvH-CtEO-zpIHjz
LV Write Access read/write
LV Creation host, time localhost, 2020-02-27 23:30:51 -0500
LV Status available
# open 2
LV Size 2.00 GiB
Current LE 512
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:1
--- Logical volume ---
LV Path /dev/centos/root
LV Name root
VG Name centos
LV UUID ZzVT9H-lHCv-lbjh-xsMU-uDM9-17Yp-ThoiF9
LV Write Access read/write
LV Creation host, time localhost, 2020-02-27 23:30:51 -0500
LV Status available
# open 1
LV Size <17.00 GiB
Current LE 4351
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:0
3.3 Increase the logical volume capacity-lvextend
Note: To modify the size of lv and file system, you must first unmount lv and file system (umount)
格式：
lvextend -L +10G /dev/vg1/lv1 先增加lv的大小
xfs_growfs /dev/vg1/lv1 再修改文件系统的大小
3.3.1 Uninstall first, increase lv capacity
[root@xxx ~]# :umount /dev/mapper/vg1-lv1
You have new mail in /var/spool/mail/root
[root@xxx ~]# :df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 17G 2.7G 15G 16% /
devtmpfs 475M 0 475M 0% /dev
tmpfs 487M 0 487M 0% /dev/shm
tmpfs 487M 7.7M 479M 2% /run
tmpfs 487M 0 487M 0% /sys/fs/cgroup
/dev/sdc1 20G 483M 20G 3% /disk/guazai4
/dev/sdb1 10G 33M 10G 1% /disk/guazai3
/dev/sda1 1014M 133M 882M 14% /boot
tmpfs 98M 0 98M 0% /run/user/0
[root@xxx ~]# :lvextend -L +5G /dev/vg1/lv1
Size of logical volume vg1/lv1 changed from 15.00 GiB (7680 extents) to 20.00 GiB (10240 extents).
Logical volume vg1/lv1 successfully resized.
You have new mail in /var/spool/mail/root
[root@xxx ~]# :mount /dev/vg1/lv1 /disk/guazai5
[root@xxx ~]# :df -h | grep /disk/guazai5
/dev/mapper/vg1-lv1 15G 33M 15G 1% /disk/guazai5
After unmounting the mount point, after we increase the size of lv, we mount and check, the actual capacity has not increased, so
3.3.2 Modify the size of the file system
[root@xxx ~]# :xfs_growfs /dev/vg1/lv1
meta-data=/dev/mapper/vg1-lv1 isize=512 agcount=4, agsize=983040 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=3932160, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 3932160 to 5242880
You have new mail in /var/spool/mail/root
[root@xxx ~]# :df -h | grep /disk/guazai5
/dev/mapper/vg1-lv1 20G 33M 20G 1% /disk/guazai5
You can see that the capacity has been updated (15G + 5G becomes 20G)
3.4 Reduce logical volume capacity—lvreduce
Note: lv modify the size and file system, you must uninstall (umount) First lv and file systems
Note: do a backup
Format:
lvreduce -L + 10G / dev / vg1 / lv1 Specifies how much the partition is reduced
mkfs.xfs -f / dev / vg1 / lv1 Then reformat, mount, view
Note: The xfs file system only supports expansion by default, and does not support shrinking, so, it cannot be truly lossless ... (forced demonstration)
3.4.1 First unmount the mount point and specify the reduced partition size
[root@xxx ~]# :df -h | grep /disk/guazai5
/dev/mapper/vg1-lv1 20G 33M 20G 1% /disk/guazai5
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[root@xxx ~]# :umount /dev/mapper/vg1-lv1
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[root@xxx ~]# :lvreduce -L 5G /dev/mapper/vg1-lv1
WARNING: Reducing active logical volume to 5.00 GiB.
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce vg1/lv1? [y/n]: Y
Size of logical volume vg1/lv1 changed from 20.00 GiB (10240 extents) to 5.00 GiB (2560 extents).
Logical volume vg1/lv1 successfully resized.
3.4.2 Force reformatting, mounting, viewing
[root@xxx ~]# :mkfs.xfs -f /dev/mapper/vg1-lv1
meta-data=/dev/mapper/vg1-lv1 isize=512 agcount=4, agsize=327680 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=1310720, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
You have new mail in /var/spool/mail/root
[root@xxx ~]# :mount /dev/vg1/lv1 /disk/guazai5
[root@xxx ~]# :df -h | grep /disk/guazai5
/dev/mapper/vg1-lv1 5.0G 33M 5.0G 1% /disk/guazai5
At this point, the size of the capacity we have checked becomes 5G.
Note: Restore the backup
