July 15, 2016

How To - Work with LVM (Logical Volume Management)

[root@server ~]# blkid

/dev/xvdc1: UUID="db67089c-1455-4ebc-9b25-e872c013452e" TYPE="swap"
/dev/xvda1: UUID="765e3d12-202a-4c30-9d94-e03d9e402fd0" TYPE="ext4"
/dev/xvdb1: PARTLABEL="primary" PARTUUID="cdfcfae9-29e1-4b8c-b38f-8669377d17ee"
/dev/xvdd1: PARTLABEL="primary" PARTUUID="ae1b9a6a-8319-4743-a96e-c23349d3cbe8"
/dev/xvde1: PARTLABEL="primary" PARTUUID="2f497396-0c59-4b3b-bc9c-3c29a19b06fe"

[root@server ~]# pvcreate /dev/xvdb1 /dev/xvdd1 /dev/xvde1

Physical volume "/dev/xvdb1" successfully created
Physical volume "/dev/xvdd1" successfully created
Physical volume "/dev/xvde1" successfully created

[root@server ~]# blkid

/dev/xvdc1: UUID="db67089c-1455-4ebc-9b25-e872c013452e" TYPE="swap"
/dev/xvda1: UUID="765e3d12-202a-4c30-9d94-e03d9e402fd0" TYPE="ext4"
/dev/xvdb1: UUID="2yeI89-vSum-nWEV-V2y1-eTtp-7Tay-uo4rvZ" TYPE="LVM2_member" PARTLABEL="primary" PARTUUID="298f6c66-d5ec-4c79-aa93-6e906e62e64d"
/dev/xvdd1: UUID="9Gfbme-k4dn-WlOT-qoGj-nfwB-4DBO-43eqVD" TYPE="LVM2_member" PARTLABEL="primary" PARTUUID="ae1b9a6a-8319-4743-a96e-c23349d3cbe8"
/dev/xvde1: UUID="37dsrq-dU7T-ZqVD-SKhz-1tii-rqwp-dZU2qV" TYPE="LVM2_member" PARTLABEL="primary" PARTUUID="2f497396-0c59-4b3b-bc9c-3c29a19b06fe"

[root@server ~]# pvremove /dev/xvdb1 /dev/xvdd1 /dev/xvde1

Labels on physical volume "/dev/xvdb1" successfully wiped
Labels on physical volume "/dev/xvdd1" successfully wiped
Labels on physical volume "/dev/xvde1" successfully wiped

  [root@server ~]# pvdisplay

"/dev/xvdb1" is a new physical volume of "75.00 GiB"
--- NEW Physical volume ---
PV Name               /dev/xvdb1
VG Name               
PV Size               75.00 GiB
Allocatable           NO
PE Size               0   
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               L4t8Dd-dJ0X-Fxg7-6qoX-B0VZ-mm0m-R3f3GO

"/dev/xvde1" is a new physical volume of "75.00 GiB"
--- NEW Physical volume ---
PV Name               /dev/xvde1
VG Name               
PV Size               75.00 GiB
Allocatable           NO
PE Size               0   
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               CFYpzt-PBBA-3DDM-PxOL-kROV-Jne1-Pnsu5u

"/dev/xvdd1" is a new physical volume of "75.00 GiB"
--- NEW Physical volume ---
PV Name               /dev/xvdd1
VG Name               
PV Size               75.00 GiB
Allocatable           NO
PE Size               0   
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               nelzUy-4BCN-5HLp-h0oz-Dne6-mwE7-bqL01N

[root@server ~]# vgcreate jbod /dev/xvdb1 /dev/xvde1 /dev/xvdd1

Volume group "jbod" successfully created

[root@server ~]# vgcreate jbod /dev/xvdb1 /dev/xvde1 /dev/xvdd1

Volume group "jbod" successfully created

[root@server ~]# vgdisplay
--- Volume group ---
VG Name               jbod
System ID             
Format                lvm2
Metadata Areas        3
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                3
Act PV                3
VG Size               224.99 GiB
PE Size               4.00 MiB
Total PE              57597
Alloc PE / Size       0 / 0   
Free  PE / Size       57597 / 224.99 GiB
VG UUID               wKxBdF-H1Kq-fDh3-Xwg1-u5ZU-T8As-r5Zo66

[root@server ~]# vgremove jbod

Volume group "jbod" successfully removed

[root@server ~]# lvcreate -n Entire_Disk jbod -l 100%VG

Logical volume "Entire_Disk" created.

[root@server ~]# lvdisplay
--- Logical volume ---
LV Path                /dev/jbod/Entire_Disk
LV Name                Entire_Disk
VG Name                jbod
LV UUID                cSkFsK-rJFN-wpJT-Nm21-JYBB-1GY2-35JUmG
LV Write Access        read/write
LV Creation host, time server, 2016-07-15 17:06:42 -0400
LV Status              available
# open                 0
LV Size                224.99 GiB
Current LE             57597
Segments               3
Allocation             inherit
Read ahead sectors     auto
- currently set to     8192
Block device           253:0

root@server ~]# lvreduce -L25G /dev/jbod/Entire_Disk

WARNING: Reducing active logical volume to 25.00 GiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce Entire_Disk? [y/n]: y
Size of logical volume jbod/Entire_Disk changed from 224.99 GiB (57597 extents) to 25.00 GiB (6400 extents).
Logical volume Entire_Disk successfully resized.

[root@server ~]# lvcreate -n Half_Disk jbod -l 50%VG

Logical volume "Half_Disk" created.

[root@server ~]# lvdisplay

--- Logical volume ---
LV Path                /dev/jbod/Entire_Disk
LV Name                Entire_Disk
VG Name                jbod
LV UUID                cSkFsK-rJFN-wpJT-Nm21-JYBB-1GY2-35JUmG
LV Write Access        read/write
LV Creation host, time server, 2016-07-15 17:06:42 -0400
LV Status              available
# open                 0
LV Size                25.00 GiB
Current LE             6400
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     8192
Block device           253:0

--- Logical volume ---
LV Path                /dev/jbod/Half_Disk
LV Name                Half_Disk
VG Name                jbod
LV UUID                YVt4KA-3F1w-9yG9-H9I3-ffVS-OlBh-tfJKYk
LV Write Access        read/write
LV Creation host, time server, 2016-07-15 17:12:11 -0400
LV Status              available
# open                 0
LV Size                112.49 GiB
Current LE             28798
Segments               2
Allocation             inherit
Read ahead sectors     auto
- currently set to     8192
Block device           253:1

[root@server ~]# lvextend -L50G /dev/jbod/Entire_Disk

Size of logical volume jbod/Entire_Disk changed from 25.00 GiB (6400 extents) to 50.00 GiB (12800 extents).
Logical volume Entire_Disk successfully resized.

[root@server ~]# lvdisplay

--- Logical volume ---
LV Path                /dev/jbod/Entire_Disk
LV Name                Entire_Disk
VG Name                jbod
LV UUID                cSkFsK-rJFN-wpJT-Nm21-JYBB-1GY2-35JUmG
LV Write Access        read/write
LV Creation host, time bria9733-eino1, 2016-07-18 17:06:42 -0400
LV Status              available
# open                 0
LV Size                50.00 GiB
Current LE             12800
Segments               3
Allocation             inherit
Read ahead sectors     auto
- currently set to     8192
Block device           253:0

--- Logical volume ---
LV Path                /dev/jbod/Half_Disk
LV Name                Half_Disk
VG Name                jbod
LV UUID                YVt4KA-3F1w-9yG9-H9I3-ffVS-OlBh-tfJKYk
LV Write Access        read/write
LV Creation host, time bria9733-eino1, 2016-07-18 17:12:11 -0400
LV Status              available
# open                 0
LV Size                112.49 GiB
Current LE             28798
Segments               2
Allocation             inherit
Read ahead sectors     auto
- currently set to     8192
Block device           253:1

[root@server ~]# mkfs.ext4 /dev/jbod/Entire_Disk

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
3276800 inodes, 13107200 blocks
655360 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2162163712
400 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, 7962624, 11239424

Allocating group tables: done                            
Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

[root@server ~]# mount /dev/jbod/Entire_Disk /mnt/

[root@server ~]# df -h

Filesystem                    Size  Used Avail Use% Mounted on
/dev/xvda1                     20G  1.7G   17G  10% /
devtmpfs                      233M     0  233M   0% /dev
tmpfs                         242M     0  242M   0% /dev/shm
tmpfs                         242M   21M  222M   9% /run
tmpfs                         242M     0  242M   0% /sys/fs/cgroup
tmpfs                          49M     0   49M   0% /run/user/1001
/dev/mapper/jbod-Entire_Disk   50G   53M   47G   1% /mnt

brian4286

Brian has spent more than fifteen years as Unix enthusiast, specalising in systems administration and solutions architecture for SMB's to Fortune 100 companies. His career has focused on emerging and niche technologies to major advancements in the industry - most notibly cloud.