Storage technology plays a important role in improving the
availability, performance, and ability to manage Linux servers.
One of the most useful and helpful technology to linux system
administrator is Linux Logical Volume Manager(LVM), version 2 (or LVM 2).
LVM is a widely-used technique and extremely flexible disk
management scheme for deploying logical rather than physical storage. With LVM,
system administrator can easily resize and extend the logical drive when it is
required.
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The following steps will describe how to create LVM in Linux
CentOS 7 or RHEL 7
How to Create Lvm in Linux Step by Step
1. Add the new 20GB vdisk from the ESXi or vCenter :
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2. create a new Partiton using fdisk tool and select partition type LVM :
[root@centos7 ~]# fdisk /dev/sdb
Welcome to fdisk (util-linux 2.23.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Device does not contain a recognized partition table
Building a new DOS disklabel with disk identifier 0xfd3bf27d.
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-41943039, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039):
Using default value 41943039
Partition 1 of type Linux and of size 20 GiB is set
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0xfd3bf27d
Device Boot Start End Blocks Id System
/dev/sdb1 2048 41943039 20970496 83 Linux
Command (m for help): t
Selected partition 1
Hex code (type L to list all codes): L
0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris
1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT-
2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT-
3 XENIX usr 3c PartitionMagic 84 OS/2 hidden C: c6 DRDOS/sec (FAT-
4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx
5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data
6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / .
7 HPFS/NTFS/exFAT 4d QNX4.x 88 Linux plaintext de Dell Utility
8 AIX 4e QNX4.x 2nd part 8e Linux LVM df BootIt
9 AIX bootable 4f QNX4.x 3rd part 93 Amoeba e1 DOS access
a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O
b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor
c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi eb BeOS fs
e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD ee GPT
f W95 Ext'd (LBA) 54 OnTrackDM6 a6 OpenBSD ef EFI (FAT-12/16/
10 OPUS 55 EZ-Drive a7 NeXTSTEP f0 Linux/PA-RISC b
11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f1 SpeedStor
12 Compaq diagnost 5c Priam Edisk a9 NetBSD f4 SpeedStor
14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f2 DOS secondary
16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ fb VMware VMFS
17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fc VMware VMKCORE
18 AST SmartSleep 65 Novell Netware b8 BSDI swap fd Linux raid auto
1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fe LANstep
1c Hidden W95 FAT3 75 PC/IX be Solaris boot ff BBT
1e Hidden W95 FAT1 80 Old Minix
Hex code (type L to list all codes): 8e
Changed type of partition 'Linux' to 'Linux LVM'
Command (m for help): p
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0xfd3bf27d
Device Boot Start End Blocks Id System
/dev/sdb1 2048 41943039 20970496 8e Linux LVM
3. Initializes the partition /dev/sdb1 as an LVM physical volume :
[root@centos7 ~]# pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created
4. Scanning for Block Devices:
[root@centos7 ~]# lvmdiskscan
/dev/centos/swap [ 2.00 GiB]
/dev/sda1 [ 500.00 MiB]
/dev/centos/root [ 27.51 GiB]
/dev/sda2 [ 29.51 GiB] LVM physical volume
/dev/sdb1 [ 20.00 GiB] LVM physical volume
2 disks
1 partition
0 LVM physical volume whole disks
2 LVM physical volumes
5. Displaying Physical Volumes :
There are
three commands you can use to display properties of LVM physical volumes: pvs,
pvdisplay, and pvscan.
pvdisplay, and pvscan.
The
pvdisplay command provides a verbose multi-line output for each physical
volume. It displays
physical properties (size, extents, volume group, etc.) in a fixed format.
physical properties (size, extents, volume group, etc.) in a fixed format.
[root@centos7 ~]# pvdisplay
--- Physical volume ---
PV Name /dev/sda2
VG Name centos
PV Size 29.51 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 7554
Free PE 0
Allocated PE 7554
PV UUID JvDOto-KDiF-gtca-TveX-ne9M-frsB-qsP1aJ
"/dev/sdb1" is a new physical volume of "20.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 20.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID rJ8wl7-xzIN-2qqV-ov7Z-lHKe-ELge-aAV29V
The pvscan
command scans all supported LVM block devices in the system for physical
volumes
[root@centos7 ~]# pvscan
PV /dev/sda2 VG centos lvm2 [29.51 GiB / 0 free]
PV /dev/sdb1 lvm2 [20.00 GiB]
Total: 2 [49.51 GiB] / in use: 1 [29.51 GiB] / in no VG: 1 [20.00 GiB]
6. Create volume group name vg_newlvm and add /dev/sdb1 partition into the group.
[root@centos7 ~]# vgcreate vg_newlvm /dev/sdb1
Volume group "vg_newlvm" successfully created
If you have
more than one partition, you can add multiple partition in single command. This
command creates a local volume named vg_newlvm that contains physical volumes
/dev/sdb1 and /dev/sdc1 :
[root@centos7 ~]# vgcreate vg_newlvm /dev/sdb1 /dev/sdc1
7. Creates a logical volume called centos7_newvol that uses all of the unallocated space in the volume group vg_newlvm :
[root@centos7 ~]# lvcreate --name centos7_newvol -l 100%FREE vg_newlvm
Logical volume "centos7_newvol" created
8. Display the created logical volumes :
[root@centos7 ~]# lvdisplay
..
..
--- Logical volume ---
LV Path /dev/vg_newlvm/centos7_newvol
LV Name centos7_newvol
VG Name vg_newlvm
LV UUID szlkNP-0lwe-f59Z-PJVU-X7pG-unBL-qN10D4
LV Write Access read/write
LV Creation host, time centos7.ehowstuff.local, 2015-01-25 15:15:48 +0800
LV Status available
# open 0
LV Size 20.00 GiB
Current LE 5119
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 8192
Block device 253:2
9. Use the mkfs command to format a newly
created LVM :
[root@centos7 ~]# mkfs.ext4 /dev/vg_newlvm/centos7_newvol
mke2fs 1.42.9 (28-Dec-2013)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
1310720 inodes, 5241856 blocks
262092 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2153775104
160 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
10. Create the mount point and mount the new LVM :
[root@centos7 ~]# mkdir -p /data
[root@centos7 ~]# mount /dev/vg_newlvm/centos7_newvol /data
11. Verify thew new disk layout :
[root@centos7 ~]# df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/centos-root 28260132 9191032 17610516 35% /
devtmpfs 1935888 0 1935888 0% /dev
tmpfs 1941892 0 1941892 0% /dev/shm
tmpfs 1941892 8728 1933164 1% /run
tmpfs 1941892 0 1941892 0% /sys/fs/cgroup
/dev/sda1 487634 73191 384747 16% /boot
tmpfs 1941892 8728 1933164 1% /var/named/chroot/run/named
/dev/mapper/vg_newlvm-centos7_newvol 20507216 45080 19397384 1% /data
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