Implementation of logical volume (lvm) in linux

1. Partition and convert lvm format

[root@localhost ~]# fdisk -cu /dev/sdbDevice contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabelBuilding a new DOS disklabel with disk identifier 0xd8e8fb90.Changes will remain in memory only, until you decide to write them.After that, of course, the previous content won't be recoverable.Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)Command (m for help): nCommand actione   extendedp   primary partition (1-4)pPartition number (1-4): 1First sector (2048-4485119, default 2048):Using default value 2048Last sector, +sectors or +size{K,M,G} (2048-4485119, default 4485119): +200MCommand (m for help): nCommand actione   extendedp   primary partition (1-4)pPartition number (1-4): 2First sector (411648-4485119, default 411648):Using default value 411648Last sector, +sectors or +size{K,M,G} (411648-4485119, default 4485119): +200MCommand (m for help): nCommand actione   extendedp   primary partition (1-4)pPartition number (1-4): 3First sector (821248-4485119, default 821248):Using default value 821248Last sector, +sectors or +size{K,M,G} (821248-4485119, default 4485119): +200MCommand (m for help): nCommand actione   extendedp   primary partition (1-4)pSelected partition 4First sector (1230848-4485119, default 1230848):Using default value 1230848Last sector, +sectors or +size{K,M,G} (1230848-4485119, default 4485119): +200MCommand (m for help): pDisk /dev/sdb: 2296 MB, 2296381440 bytes255 heads, 63 sectors/track, 279 cylinders, total 4485120 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xd8e8fb90Device Boot      Start         End      Blocks   Id  System/dev/sdb1            2048      411647      204800   83  Linux/dev/sdb2          411648      821247      204800   83  Linux/dev/sdb3          821248     1230847      204800   83  Linux/dev/sdb4         1230848     1640447      204800   83  LinuxCommand (m for help): tPartition number (1-4): 1Hex code (type L to list codes): L0  Empty           24  NEC DOS         81  Minix / old Lin bf  Solaris1  FAT12           39  Plan 9          82  Linux swap / So c1  DRDOS/sec (FAT-2  XENIX root      3c  PartitionMagic  83  Linux           c4  DRDOS/sec (FAT-3  XENIX usr       40  Venix 80286     84  OS/2 hidden C:  c6  DRDOS/sec (FAT-4  FAT16 <32M      41  PPC PReP Boot   85  Linux extended  c7  Syrinx5  Extended        42  SFS             86  NTFS volume set da  Non-FS data6  FAT16           4d  QNX4.x          87  NTFS volume set db  CP/M / CTOS / .7  HPFS/NTFS       4e  QNX4.x 2nd part 88  Linux plaintext de  Dell Utility8  AIX             4f  QNX4.x 3rd part 8e  Linux LVM       df  BootIt9  AIX bootable    50  OnTrack DM      93  Amoeba          e1  DOS accessa  OS/2 Boot Manag 51  OnTrack DM6 Aux 94  Amoeba BBT      e3  DOS R/Ob  W95 FAT32       52  CP/M            9f  BSD/OS          e4  SpeedStorc  W95 FAT32 (LBA) 53  OnTrack DM6 Aux a0  IBM Thinkpad hi eb  BeOS fse  W95 FAT16 (LBA) 54  OnTrackDM6      a5  FreeBSD         ee  GPTf  W95 Ext'd (LBA) 55  EZ-Drive        a6  OpenBSD         ef  EFI (FAT-12/16/10  OPUS            56  Golden Bow      a7  NeXTSTEP        f0  Linux/PA-RISC b11  Hidden FAT12    5c  Priam Edisk     a8  Darwin UFS      f1  SpeedStor12  Compaq diagnost 61  SpeedStor       a9  NetBSD          f4  SpeedStor14  Hidden FAT16 <3 63  GNU HURD or Sys ab  Darwin boot     f2  DOS secondary16  Hidden FAT16    64  Novell Netware  af  HFS / HFS+      fb  VMware VMFS17  Hidden HPFS/NTF 65  Novell Netware  b7  BSDI fs         fc  VMware VMKCORE18  AST SmartSleep  70  DiskSecure Mult b8  BSDI swap       fd  Linux raid auto1b  Hidden W95 FAT3 75  PC/IX           bb  Boot Wizard hid fe  LANstep1c  Hidden W95 FAT3 80  Old Minix       be  Solaris boot    ff  BBT1e  Hidden W95 FAT1Hex code (type L to list codes): 8eChanged system type of partition 1 to 8e (Linux LVM)Command (m for help): tPartition number (1-4): 2Hex code (type L to list codes): 8eChanged system type of partition 2 to 8e (Linux LVM)Command (m for help): tPartition number (1-4): 3Hex code (type L to list codes): 8eChanged system type of partition 3 to 8e (Linux LVM)Command (m for help): tPartition number (1-4): 4Hex code (type L to list codes): 8eChanged system type of partition 4 to 8e (Linux LVM)Command (m for help): pDisk /dev/sdb: 2296 MB, 2296381440 bytes255 heads, 63 sectors/track, 279 cylinders, total 4485120 sectorsUnits = sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisk identifier: 0xd8e8fb90Device Boot      Start         End      Blocks   Id  System/dev/sdb1            2048      411647      204800   8e  Linux LVM/dev/sdb2          411648      821247      204800   8e  Linux LVM/dev/sdb3          821248     1230847      204800   8e  Linux LVM/dev/sdb4         1230848     1640447      204800   8e  Linux LVMCommand (m for help): wThe partition table has been altered!Calling ioctl() to re-read partition table.Syncing disks.[root@localhost ~]#

2. Convert the partition to the pv physical volume, add the pv to a vg group, and draw the lv logical volume from the vg.

[Root @ localhost ~] # Pvcreate/dev/sdb {1, 2, 3, 4} -- convert partitions to Physical volumes Physical volume "/dev/sdb1" successfully createdPhysical volume "/dev/sdb2" successfully createdPhysical volume "/dev/sdb3" successfully createdPhysical volume "/ dev/sdb4 "successfully created [root @ localhost ~] # Pvscan -- view the physical volume PV/dev/sda2 VG VolGroup lvm2 [7.51 GiB/0 free] PV/dev/sdb1 lvm2 [200.00 MiB] PV/dev/sdb2 lvm2 [200.00 MiB] PV/dev/sdb3 lvm2 [200.00 MiB] PV/dev/sdb4 lvm2 [200.00 MiB] Total: 5 [8.29 GiB]/in use: 1 [7.51 GiB]/in no VG: 4 [800.00 MiB] [root @ localhost ~] # Vgcreate vg0/dev/sdb {1, 2, 3} -- add physical volumes 1, 2, and 3 to the Volume group "vg0" successfully created [root @ localhost ~] # Vgscan -- view the volume group Reading all physical volumes. this may take a while... found volume group "vg0" using metadata type lvm2Found volume group "VolGroup" using metadata type lvm2 [root @ localhost ~] # Lvcreate-n test-L 150 M vg0 -- separate the pv logical volume from the volume group Rounding up size to full physical extent 152.00 MiBLogical volume "test" created [root @ localhost ~] # Lvcreate-n test1-L 150 M vswitchrounding up size to full physical extent 152.00 MiBLogical volume "test1" created [root @ localhost ~] # LvscanACTIVE '/dev/vg0/test' [152.00 MiB] inheritACTIVE'/dev/vg0/test1 '[152.00 MiB] inheritACTIVE'/dev/VolGroup/lv_root '[6.51 GiB] inheritACTIVE '/dev/VolGroup/lv_swap' [1.00 GiB] inherit [root @ localhost ~] # Mkfs. ext4/dev/vg0/test -- format the physical volume mke2fs 1.41.12 (17-May-2010) Filesystem label = OS type: LinuxBlock size = 1024 (log = 0) fragment size = 1024 (log = 0) Stride = 0 blocks, Stripe width = 0 blocks38912 inodes, 155648 blocks7782 blocks (5.00%) reserved for the super userFirst data block = 1 Maximum filesystem blocks = 6737100819 block groups8192 blocks per group, 8192 fragments per group2048 inodes per groupSuperblock B Ackups stored on blocks: 8193,245 77, 40961,573 45, 73729 Writing inode tables: doneCreating journal (4096 blocks): doneWriting superblocks and filesystem accounting information: doneThis filesystem will be automatically checked every 26 mounts or180 days, whichever comes first. use tune2fs-c or-I to override. [root @ localhost ~] # Mount/dev/vg0/test/mnt/sdb -- mount [root @ localhost ~] # Mkdir/mnt/sdb/12 -- you can use [root @ localhost ~] # Ll/mnt/sdb/total 14drwxr-xr-x. 2 root 1024 Jan 9 12drwx ------. 2 root 12288 Jan 9 lost + found [root @ localhost ~] #

3. Expand the volume group (vg) and expand the logical volume (pv)

[Root @ localhost ~] # Vgdisplay vg0 --- Volume group --- VG Name vg0System IDFormat lvm2Metadata Areas 3 Metadata Sequence No 3VG Access read/writeVG Status resizableMAX LV 0Cur LV 2 Open LV 1Max PV 0Cur PV 3Act PV 3VG Size 588.00 MiB -- The volume group Size is 588MPE Size 4.00 MiBTotal PE 147 Alloc PE/Size 76/304 .00 MiBFree PE/Size 71/284 .00 MiBVG UUID Pau9QC-3eru-dhF2-nJ3C-clpZ-vbDy-X023YM [root @ localhost ~] # Lvdisplay/dev/vg0/test -- View lv (test) --- Logical volume --- LV Path/dev/vg0/testLV Name testVG Name v1_lv UUID uY4frU-gSy4-Pkwc-76Tw-Nh04-M7Ob-Tz8fPYLV Write Access read/writeLV Creation host, time localhost. localdomain, 15:22:40 + 0800LV Status available # open 1LV Size 152.00 MiB -- lv Size is 152 MCurrent LE 38 Segments 1 Allocation inheritRead ahead sectors auto-currently set to 256 Block d Evice 253: 2 [root @ localhost ~] # Df-THFilesystem Type Size Used Avail Use % Mounted on/dev/mapper/VolGroup-lv_rootext4 6.9G 6.4G 171 M 98%/tmpfs 262 M 0 262 M 0%/dev/shm/dev /sda1 ext4 508 M 48 M 435 M 10%/boot/dev/mapper/vg0-testext4 155 M 5.8 M 141 M 4%/mnt/sdb -- the size after mounting is 155 M [root @ localhost ~] # Lvextend-L + 50 M/dev/vg0/test -- increase the logical volume test by 50 MRounding size to boundary between physical extents: 52.00 MiBExtending logical volume test to 204.00 MiBLogical volume test successfully resized [root @ localhost ~] # Lvdisplay/dev/vg0/test -- display the size of the test Logical volume --- LV Path/dev/vg0/testLV Name testVG Name v1_lv UUID uY4frU-gSy4-Pkwc-76Tw-Nh04-M7Ob-Tz8fPYLV Write Access read/writeLV Creation host, time localhost. localdomain, 15:22:40 + 0800LV Status available # open 1LV Size 204.00 MiB -- Size changed to 204 MCurrent LE 51 Segments 2 Allocation inheritRead ahead sectors auto-currently set to 256 Block devi Ce 253: 2 [root @ localhost ~] # Df-THFilesystem Type Size Used Avail Use % Mounted on/dev/mapper/VolGroup-lv_rootext4 6.9G 6.4G 171 M 98%/tmpfs 262 M 0 262 M 0%/dev/shm/dev /sda1 ext4 508 M 48 M 435 M 10%/boot/dev/mapper/vg0-testext4 155 M 5.8 M 141 M 4%/mnt/sdb -- the mounted directory has not changed [root @ localhost ~] # Resize2fs-f/dev/vg0/test -- force modify the partition size resize2fs 1.41.12 (17-May-2010) filesystem at/dev/vg0/test is mounted on/mnt/sdb; on-line resizing requiredold desc_blocks = 1, new_desc_blocks = 1 sort Ming an on-line resize of/dev/vg0/test to 208896 (1 k) blocks. the filesystem on/dev/vg0/test is now 208896 blocks long. [root @ localhost ~] # Df-THFilesystem Type Size Used Avail Use % Mounted on/dev/mapper/VolGroup-lv_rootext4 6.9G 6.4G 171 M 98%/tmpfs 262 M 0 262 M 0%/dev/shm/dev /sda1 ext4 508 M 48 M 435 M 10%/boot/dev/mapper/vg0-testext4 208 M 6.1 M 191 M 4%/mnt/sdb -- size changed [root @ localhost ~] # [Root @ localhost ~] # Vgdisplay vg0 -- View Volume group --- VG Name v1_system IDFormat lvm2Metadata Areas 3 Metadata Sequence No 3VG Access read/writeVG Status resizableMAX LV 0Cur LV 2 Open LV 1Max PV 0Cur PV 3Act PV 3VG Size 588.00 MiB -- the volume group Size is 588MPE Size 4.00 MiBTotal PE 147 Alloc PE/Size 76/304 .00 MiBFree PE/Size 71/284 .00 MiBVG UUID Pau9QC-3eru-dhF2-nJ3C-clpZ-vbDy-X023YM [root @ localhost ~] # Vgextend vg0/dev/sdb4 -- add partition 4 to the Volume group "vg0" successfully extended [root @ localhost ~] In the vg Volume group # Vgdisplay vg0 -- View Volume group --- VG Name v1_system IDFormat lvm2Metadata Areas 4 Metadata Sequence No 4VG Access read/writeVG Status resizableMAX LV 0Cur LV 2 Open LV 1Max PV 0Cur PV 4Act PV 4VG Size 784.00 MiB -- the volume group Size is 784MPE Size 4.00 MiBTotal PE 196 Alloc PE/Size 76/304 .00 MiBFree PE/Size 120/480 .00 MiBVG UUID Pau9QC-3eru-dhF2-nJ3C-clpZ-vbDy-X023YM [root @ localhost ~] #

4. Reduce the volume group (vg) and the logical volume (pv)

[Root @ localhost ~] # Pvscan -- view the volume group size PV/dev/sdb1 VG vg0 lvm2 [196.00 MiB/0 free] PV/dev/sdb2 VG vg0 lvm2 [196.00 MiB/36.00 MiB free] PV/ dev/sdb3 VG vg0 lvm2 [196.00 MiB/196.00 MiB free] PV/dev/sdb4 VG vg0 lvm2 [196.00 MiB/196.00 MiB free] PV/dev/sda2 VG VolGroup lvm2 [7.51 giB/0 free] Total: 5 [8.27 GiB]/in use: 5 [8.27 GiB]/in no VG: 0 [0] [root @ localhost ~] # Vgreduce vg0/dev/sdb4 -- Remove physical volume 4 from the vg volume group Removed "/dev/sdb4" from volume group "vg0" [root @ localhost ~] # Pvscan -- view the size of the vg volume group PV/dev/sdb1 VG vg0 lvm2 [196.00 MiB/0 free] PV/dev/sdb2 VG vg0 lvm2 [196.00 MiB/36.00 MiB free] PV/dev/sdb3 VG vg0 lvm2 [196.00 MiB/196.00 MiB free] PV/dev/sda2 VG VolGroup lvm2 [7.51 GiB/0 free] PV/dev/sdb4 lvm2 [200.00 MiB] Total: 5 [8.28 GiB]/in use: 4 [8.08 GiB]/in no VG: 1 [200.00 MiB] [root @ localhost ~] # Vgdisplay vg0 -- view the Volume group size --- Volume group --- VG Name v1_system IDFormat lvm2Metadata Areas 3 Metadata Sequence No 6VG Access read/writeVG Status resizableMAX LV 0Cur LV 2 Open LV 1Max PV 0Cur PV 3Act PV 3VG Size 588.00 MiBPE Size 4.00 MiBTotal PE 147 Alloc PE/Size 89/356 .00 MiBFree PE/Size 58/232 .00 MiBVG UUID Pau9QC-3eru-dhF2-nJ3C-clpZ-vbDy-X023YM [root @ localhost ~] # Umount/mnt/sdb/-- when reducing the logical volume, you must uninstall [root @ localhost ~] # Resize2fs-f/dev/vg0/test 100 M -- change the logical volume size by 100Mresize2fs 1.41.12 (17-May-2010) resizing the filesystem on/dev/vg0/test to 102400 (1 k) blocks. the filesystem on/dev/vg0/test is now 102400 blocks long. [root @ localhost ~] # Resize2fs-f/dev/vg0/test 100Mresize2fs 1.41.12 (17-May-2010) Resizing the filesystem on/dev/vg0/test to 102400 (1 k) blocks. the filesystem on/dev/vg0/test is now 102400 blocks long. [root @ localhost ~] # Lvreduce-L 100 M/dev/vg0/test -- Adjust the logical volume test size to 100 MWARNING: Variable active logical volume to 100.00 MiBTHIS may destroy your data (filesystem etc .) do you really want to reduce test? [Y/n]: y -- enter y to confirm the configuration of the volume test to 100.00 MiBLogical volume test successfully resized [root @ localhost ~] # Mount/dev/vg0/test/mnt/sdb/-- mount the logical volume [root @ localhost ~] # Df-THFilesystem Type Size Used Avail Use % Mounted on/dev/mapper/VolGroup-lv_rootext4 6.9G 6.4G 171 M 98%/tmpfs 262 M 0 262 M 0%/dev/shm/dev /sda1 ext4 508 M 48 M 435 M 10%/boot/dev/mapper/vg0-testext4 102 M 5.8 M 91 M 7%/mnt/sdb -- Logical volume test size changed to 100 M [root @ localhost ~] #

5. Create a logical volume Snapshot

[Root @ localhost ~] # Cp-a/etc/passwd/etc/shadow/mnt/sdb/[root @ localhost ~] # Ll/mnt/sdb/total 142drwxr-xr-x. 2 root 1024 Jan 9 12drwx ------. 2 root 12288 Jan 9 lost + found-rw -------. 1 root 125811 Feb 22 2013 moduli-rw-r --. 1 root 953 Jan 9 13:09 passwd ----------. 1 root 627 Jan 9 13:09 shadow [root @ localhost ~] # Lvcreate-s-L 50 M-n sanp/dev/vg0/test -- create a 50 M logical snapshot Rounding up size to full physical extent 52.00 MiBLogical volume "sanp" created [root @ localhost ~] # Mkdir/mnt/sdb2 [root @ localhost ~] # Mount/dev/vg0/sanp/mnt/sdb2/-- mount a snapshot [root @ localhost ~] # Df-THFilesystem Type Size Used Avail Use % Mounted on/dev/mapper/VolGroup-lv_rootext4 6.9G 6.4G 171 M 98%/tmpfs 262 M 0 262 M 0%/dev/shm/dev /sda1 ext4 508 M 48 M 435 M 10%/boot/dev/mapper/vg0-testext4 102 M 6.0 M 91 M 7%/mnt/sdb -- Logical volume size/dev/mapper/vg0-sanpext4 102 M 6.0 M 91 M 7%/mnt/sdb2 -- snapshot size [root @ localhost ~] # Ll/mnt/sdb2/total 142drwxr-xr-x. 2 root 1024 Jan 9 12drwx ------. 2 root 12288 Jan 9 lost + found-rw -------. 1 root 125811 Feb 22 2013 moduli-rw-r --. 1 root 953 Jan 9 13:09 passwd ----------. 1 root 627 Jan 9 13:09 shadow [root @ localhost ~] #

6. Delete the volume group (vg), delete the physical volume (pv), and delete the logical volume (lv)

[Root @ localhost ~] # Lvscan -- view the logical volume ACTIVE Original '/dev/vg0/test' [100.00 MiB] inheritACTIVE'/dev/vg0/test1 '[152.00 MiB] inheritACTIVE Snapshot'/dev/vg0 /sanp '[52.00 MiB] inheritACTIVE Snapshot'/dev/vg0/sanp1 '[52.00 MiB] inheritACTIVE'/dev/VolGroup/lv_root '[6.51 GiB] inheritACTIVE'/dev/VolGroup /lv_swap '[ 1.00 GiB] inherit [root @ localhost ~] # Lvremove/dev/vg0/test -- remove a logical volume (all directories must be detached) Do you really want to remove active logical volume sanp? [Y/n]: y -- enter y to confirm Logical volume "sanp" successfully removedDo you really want to remove active logical volume sanp1? [Y/n]: y -- enter y to confirm Logical volume "sanp1" successfully removedDo you really want to remove active logical volume test? [Y/n]: y -- enter y to confirm Logical volume "test" successfully removed [root @ localhost ~] # Vgscan -- view the volume group (vg) Reading all physical volumes. this may take a while... found volume group "vg0" using metadata type lvm2Found volume group "VolGroup" using metadata type lvm2 [root @ localhost ~] # Vgremove vg0 -- remove volume group (vg) Do you really want to remove volume group "vg0" containing 1 logical volumes? [Y/n]: y -- enter y to confirm Do you really want to remove active logical volume test1? [Y/n]: y -- enter y to confirm Logical volume "test1" successfully removedVolume group "vg0" successfully removed [root @ localhost ~] # PvscanPV/dev/sda2 VG VolGroup lvm2 [7.51 GiB/0 free] PV/dev/sdb1 lvm2 [200.00 MiB] PV/dev/sdb2 lvm2 [200.00 MiB] PV/dev/ sdb3 lvm2 [200.00 MiB] PV/dev/sdb4 lvm2 [200.00 MiB] Total: 5 [8.29 GiB]/in use: 1 [7.51 GiB]/in no VG: 4 [800.00 MiB] [root @ localhost ~] # Pvremove/dev/sdb {1, 2, 3, 4} -- Remove physical volumes Labels on physical volume "/dev/sdb1" using wipedLabels on physical volume "/dev/sdb2" using wipedLabels on physical volume "/dev/sdb3" using wipedLabels on physical volume "/dev/sdb4" successfully wiped [root @ localhost ~] #

7. Common commands in lvm logical volumes

Pvcreate -- create a physical partition and build pvpvscan -- display a disk with pv pvdisplay -- list pvpvremove on the system -- delete the pv attribute vgcreate -- create the vg command vgscan -- find whether the vg in the system exists vgdisplay -- current System vg status vgextend -- add pvvgremove in vg -- delete a vgvgchange -- set whether vg starts vgreduce -- delete pvlvcreate in vg -- create lvlvscan -- Query System lvdisplay -- Display System lv status lvextend -- add capacity lvreduce in lv -- reduce capacity in lv lvremove -- delete lvlvresize -- Adjust the lv capacity

 

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