For a server backend (database) operations personnel, adding a volume group directory and online expansion of directories in the Linux operating system is a common operation. In large operations teams, the division of labor is quite detailed, and it may not be necessary for database operations personnel to perform directory expansion operations; this may be handled by operating system operations personnel. The following is a brief description of how to create physical volume groups, logical volumes, and mount the volume group to a newly created directory or expand it online to an existing directory in the Linux operating system.
Creating Physical and Logical Volumes and DirectoriesChecking Available Storage Devices
[root@eachroom ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 253:0 0 40G 0 disk
└─vda1 253:1 0 40G 0 part
/vdb 253:16 0 400G 0 diskPartitioning Storage Devices (can be left unpartitioned)
[root@eachroom ~]# fdisk /dev/vdb
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 0xf7bd955e.
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):
First sector (2048-838860799, default 2048): Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-838860799, default 838860799): +400G
Value out of range.
Last sector, +sectors or +size{K,M,G} (2048-838860799, default 838860799): +409590M
Partition 1 of type Linux and of size 400 GiB is set
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
[root@eachroom ~]#Creating Physical Volume Group
[root@eachroom ~]# vgcreate contos-data /dev/vdb1
Physical volume "/dev/vdb1" successfully created. Volume group "contos-data" successfully created
[root@eachroom ~]#Checking Volume Group Information
[root@eachroom ~]# lvmlvm> vgdisplay --- Volume group ---
VG Name contos-data
System ID
Format lvm2
Metadata Areas 1
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 1
Act PV 1
VG Size <399.99 GiB
PE Size 4.00 MiB
Total PE 102397
Alloc PE / Size 0 / 0
Free PE / Size 102397 / <399.99 GiB
VG UUID LeuLp9-P0Tx-F1cU-Oxyg-G6Ce-T434-3BAzYelvm>lvm>lvm> exit Exiting.
[root@eachroom ~]#Creating Logical Volume Group
[root@eachroom ~]# lvcreate -L 399G -n data-lv01 contos-data
Logical volume "data-lv01" created.
[root@eachroom ~]# Logical Volume Group Name: data-lv01
Physical Volume Group Name: contos-data
This is where the logical volume group is added to the physical volume group. If a physical volume group is not specified during the creation of the logical volume group, the system will automatically create a physical volume group and add the logical volume group to this physical volume group by default.
Checking Volume Group Information Again
[root@eachroom ~]# lvmlvm> vgdisplay --- Volume group ---
VG Name contos-data
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 1
Act PV 1
VG Size <399.99 GiB
PE Size 4.00 MiB
Total PE 102397
Alloc PE / Size 102144 / 399.00 GiB
Free PE / Size 253 / 1012.00 MiB
VG UUID LeuLp9-P0Tx-F1cU-Oxyg-G6Ce-T434-3BAzYelvm>lvm>lvm> exit Exiting.
[root@eachroom ~]#[root@eachroom ~]#[root@eachroom ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
vda 253:0 0 40G 0 disk
└─vda1 253:1 0 40G 0 part
/vdb 253:16 0 400G 0 disk
└─vdb1 253:17 0 400G 0 part └─contos--data-data--lv01 252:0 0 399G 0 lvm
[root@eachroom ~]#The logical volume group has been successfully created.
Creating New Directory
[root@eachroom ~]# mkdir /data
[root@eachroom ~]#[root@eachroom ~]#[root@eachroom ~]# ls -lrttotal 564-rw-r--r-- 1 root root 575048 Aug 15 10:22 zabbix-agent-6.0.30-release1.el7.x86_64.rpm
[root@eachroom ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 12G 0 12G 0% /dev
tmpfs 12G 0 12G 0% /dev/shm
tmpfs 12G 8.7M 12G 1% /run
tmpfs 12G 0 12G 0% /sys/fs/cgroup
dev/vda1 40G 3.4G 35G 9% /
tmpfs 2.4G 0 2.4G 0% /run/user/1000
[root@eachroom ~]#Formatting the Newly Created Logical Volume Group
[root@eachroom ~]# mkfs.ext4 /dev/mapper/contos--data-data--lv01
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
26148864 inodes, 104595456 blocks
5229772 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=22523412483192 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, 20480000, 23887872, 71663616, 78675968, 102400000
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
[root@eachroom ~]#This formats the volume group into ext4 format.
Mounting the Logical Volume Group to the Newly Created Directory
[root@eachroom ~]# mount /dev/contos-data/data-lv01 /data
[root@eachroom ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 12G 0 12G 0% /dev
tmpfs 12G 0 12G 0% /dev/shm
tmpfs 12G 8.7M 12G 1% /run
tmpfs 12G 0 12G 0% /sys/fs/cgroup
dev/vda1 40G 3.4G 35G 9% /
dev/mapper/contos--data-data--lv01 393G 73M 373G 1% /dataEditing Auto-Mount
[root@eachroom ~]# vi /etc/fstab
/dev/contos-data/data-lv01 /data ext4 defaults 1 1At this point, the volume group and directory creation is complete.
Online Expansion of Existing Directory
Checking Available Storage Devices
[root@kbsnode01 ~]# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 30G 0 disk
├─sda1 8:1 0 1G 0 part /boot
└─sda2 8:2 0 29G 0 part
├─centos-root 253:0 0 27G 0 lvm /
└─centos-swap 253:1 0 2G 0 lvm [SWAP]
sdb 8:16 0 30G 0 disk
sr0 11:0 1 4.4G 0 rom /run/media/admin/CentOS 7 x86_64
[root@kbsnode01 ~]# Here we see a 30G sdb device available.
Checking Volume Group Information
[root@kbsnode01 ~]# lvmlvm> pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created.
lvm> lvm> pvdisplay --- Physical volume ---
PV Name /dev/sda2
VG Name centos
PV Size <29.00 GiB / not usable 3.00 MiB
Allocatable yes PE Size 4.00 MiB
Total PE 7423
Free PE 1
Allocated PE 7422
PV UUID uAzNfq-axBO-b1A2-uILr-iiih-I7yI-8ORmqg
"/dev/sdb1" is a new physical volume of "29.00 GiB"
--- NEW Physical volume ---
PV Name /dev/sdb1
VG Name
PV Size 29.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID rvGqkk-HQ04-ceFG-1NAk-XDJc-IAhT-kP5jgelvm> lvm> 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 <29.00 GiB
PE Size 4.00 MiB
Total PE 7423
Alloc PE / Size 7422 / 28.99 GiB
Free PE / Size 1 / 4.00 MiB
VG UUID TmEeQp-aLi2-Wz2A-HgAK-suly-MFNf-VFiNC0lvm> Volume Group Expansion
lvm> vgextend centos /dev/sdb1
Volume group "centos" successfully extended
lvm> lvm> lvm> lvm> vgdisplay --- Volume group ---
VG Name centos
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 2
Act PV 2
VG Size 57.99 GiB
PE Size 4.00 MiB
Total PE 14846
Alloc PE / Size 7422 / 28.99 GiB
Free PE / Size 7424 / 29.00 GiB
VG UUID TmEeQp-aLi2-Wz2A-HgAK-suly-MFNf-VFiNC0lvm> lvm> lvextend -l +100%FREE /dev/centos/root
Size of logical volume centos/root changed from 26.99 GiB (6910 extents) to 55.99 GiB (14334 extents).
Logical volume centos/root successfully resized.
lvm> [root@kbsnode01 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 893M 0 893M 0% /dev
tmpfs 910M 0 910M 0% /dev/shm
tmpfs 910M 11M 900M 2% /run
tmpfs 910M 0 910M 0% /sys/fs/cgroup
dev/mapper/centos-root 27G 4.1G 23G 16% /
/dev/sda1 1014M 187M 828M 19% /boot
tmpfs 182M 24K 182M 1% /run/user/1000
/dev/sr0 4.5G 4.5G 0 100% /run/media/admin/CentOS 7 x86_64
tmpfs 182M 0 182M 0% /run/user/0
[root@kbsnode01 ~]# The above operations can be executed in the operating system interactive mode
[root@kbsnode01 ~]# vgextend centos /dev/sdb1
[root@kbsnode01 ~]# lvextend -l +100%FREE /dev/mapper/centos-rootFormatting the Logical Volume
[root@kbsnode01 ~]# xfs_growfs /dev/centos/root
meta-data=/dev/mapper/centos-root isize=512 agcount=4, agsize=1768960 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=0 spinodes=0
data = bsize=4096 blocks=7075840, imaxpct=25 = sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal bsize=4096 blocks=3455, version=2 = sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
data blocks changed from 7075840 to 14678016
[root@kbsnode01 ~]# [root@kbsnode01 ~]# [root@kbsnode01 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 893M 0 893M 0% /dev
tmpfs 910M 0 910M 0% /dev/shm
tmpfs 910M 11M 900M 2% /run
dev/mapper/centos-root 56G 4.1G 52G 8% /
/dev/sda1 1014M 187M 828M 19% /boot
tmpfs 182M 24K 182M 1% /run/user/1000
/dev/sr0 4.5G 4.5G 0 100% /run/media/admin/CentOS 7 x86_64
tmpfs 182M 0 182M 0% /run/user/0
[root@kbsnode01 ~]# Comparing the previous volume group expansion steps, we can see that 29G has been expanded to the / directory.
In summary, online expansion consists of five steps: check devices — check volume group information — extend physical volume group — extend logical volume — format logical volume.
lsblk
vgextend centos /dev/sdb1
lvextend -l +100%FREE /dev/mapper/centos-root
xfs_growfs /dev/mapper/centos/rootIf using the ext4 file format, then use the following command during formatting:
resize2fs /dev/mapper/centos/root