How to increase the hard disk space of thin provisioning vm - linux

Question

Created thin provisioning vm(centos 7) with 50 GB hard disk. But it doesnt automatically increase the space when there is a need. Can someone please tell how to increase the space of "/" directory.
[oracle#localhost ~]$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/centos-root 14G 14G 16K 100% /
devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs 1.9G 912M 985M 49% /dev/shm
tmpfs 1.9G 17M 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/sda1 497M 147M 351M 30% /boot
tmpfs 380M 0 380M 0% /run/user/1001
tmpfs 380M 0 380M 0% /run/user/1002
Below are the output of pvs command.
[root#inches-rmdev01 ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 centos lvm2 a-- 15.51g 40.00m
Below are the output of vgs command.
[root#inches-rmdev01 ~]# vgs
VG #PV #LV #SN Attr VSize VFree
centos 1 2 0 wz--n- 15.51g 40.00m
Below are the output of lvs command.
[root#inches-rmdev01 ~]# lvs
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert
root centos -wi-ao---- 13.87g
swap centos -wi-ao---- 1.60g
Below are the output of fdisk command.
[root#inches-rmdev01 ~]# fdisk -l
Disk /dev/sda: 53.7 GB, 53687091200 bytes, 104857600 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: 0x0009a61a
Device Boot Start End Blocks Id System
/dev/sda1 * 2048 1026047 512000 83 Linux
/dev/sda2 1026048 33554431 16264192 8e Linux LVM
/dev/sda3 33554432 104857599 35651584 8e Linux LVM
Disk /dev/mapper/centos-root: 14.9 GB, 14889779200 bytes, 29081600 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 /dev/mapper/centos-swap: 1719 MB, 1719664640 bytes, 3358720 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

Answer 1

In the fdisk -l output you can see that you have a 35GB disk /dev/sda3. To extend your root volume you can add this disk to LVM (Logical Volume Manager):
pvcreate /dev/sda3
This will add the unused disk /dev/sda3 as a new pv (physical volume) to LVM.
Next step is to extend your root vg (volumegroup). In your case it is easy since you've got only one vg:
vgextend centos /dev/sda3
Now you have added the 35GB disk to your vg and you can distribute it to your lv's (logical volume).
Finaly you can add as much space as you need (up to 35GB) to your root-volume with the lvextend command:
If you want to use the whole 35GB you can use:
lvextend -l +100%FREE /dev/mapper/centos-root
If you only want to add a certain ammount (i.e 1G) you can use this:
lvextend -L +1G /dev/mapper/centos-root
And finaly resize your filesystem:
resize2fs /dev/mapper/centos-root
The LVM logic is:
1. Harddisk fdisk -l
2. Physical Volume pvs
3. Volume Group vgs
4. Logical Volume lvs